Errani's breakthrough season occurred in 2012. At the Australian Open, she reached the quarterfinals in singles and was a finalist in doubles. Known as a clay-court specialist, Errani won three titles on clay going into the 2012 French Open, where she reached the finals in both the singles and doubles tournaments, winning the doubles title with her partner Roberta Vinci. They also won the doubles titles at the 2012 US Open, and the 2013 and 2014 Australian Open. By winning the 2014 Wimbledon Women's Doubles title together, Errani and Vinci became only the fifth pair in tennis history to complete a Career Grand Slam.
Her achievement in reaching the 2012 US Open singles semifinals leaves Wimbledon as the only Grand Slam tournament in which Errani has yet to make the quarterfinals in singles.
Errani was born in Bologna, Emilia-Romagna, Italy to Giorgio, a fruit and vegetable seller and Fulvia, a pharmacist. At the age of 12, her father sent her to the Nick Bollettieri Tennis Academy in Florida. At 16, she moved to Valencia, Spain, to be coached by Pablo Lozano and David Andres.
Errani competed in her first event at the $10,000 Cagliari event in her native Italy in 2002, where she lost to Sun Tiantian. She continued to compete in the ITF, where her best performance of the year was a semifinal appearance in Zaton. She continued to participate mainly on the ITF ciruit, where she won her first tournament over Lucia Jiminez in Melilla, Spain in 2005.
The first WTA title of her career was in the Internazionali Femminili di Palermo, where she defeated Mariya Koryttseva. On July 27, 2008, she captured her second career title in two weeks, defeating Anabel Medina Garrigues. She has also won six doubles WTA titles.
In 2009, Errani was the runner-up at two WTA tournaments: in Palermo and Portorož, as the defending champion in both. Errani was defeated in the first round of the 2009 French Open by defending champion Ana Ivanovic, whom she would beat in the third round three years later.
Errani reached the third round in every Grand Slam except the French Open in 2010, where she lost in the first round. At the 2010 US Open, she upset Alisa Kleybanova in the second round, before losing to eventual quarterfinalist Samantha Stosur in the third round.
Errani was a member of Fed Cup-winning Italian team in 2009 and 2010. In February 2011, she reached the final of the PTT Pattaya Open, where she was defeated by Daniela Hantuchová.
At the beginning of 2012, Errani decided to change her racquet, switching from Wilson to Babolat, opting for a heavier and slightly longer model than the last, allowing for more power and better reach. This change caused her to return her $30,000 endorsement fee to Wilson. However, she and several commentators cite the new racquet as a reason for her improved game and her entry into the top 10 of the WTA rankings. In the first five months of 2012, she won three singles titles, earning over $1.3 million in prize money. Errani herself dubbed her new racquet "Excalibur", named after the sword of King Arthur.
At the 2012 Australian Open Errani advanced to her first grand slam quarterfinal, defeating Nadia Petrova, Sorana Cîrstea, and Zheng Jie en route, before losing to Petra Kvitová. Her ranking jumped to world no. 33, a career best. At the Abierto Monterrey Open, she was the second seed and reached the semifinals, losing to eventual champion Tímea Babos, but she triumphed on the clay in Acapulco as the third seed, winning her third career title. She defeated fellow Italians Roberta Vinci, and second seed Flavia Pennetta in her last two matches. Errani fell in the opening round of Indian Wells to Vania King, and in the second round of the 2012 Sony Ericsson Open against Sloane Stephens.
As the seventh seed at the Barcelona Ladies Open, Errani stormed to her fourth career title and second of the year, not dropping a set, beating second seeded Julia Görges in the quarterfinals, Carla Suárez Navarro in the semifinals, and Dominika Cibulková in the final. Afterwards, her ranking rose to world no. 28. In the Fed Cup semifinals against the Czech Republic, Errani lost to Petra Kvitová, but beat Andrea Hlaváčková, with Italy losing the tie. On May 7, 2012 Errani won the 2012 Budapest Grand Prix, tying countrywoman Roberta Vinci for the most titles won by an Italian female in a year at three.
Her performance continued to improve when she reached the finals of the 2012 French Open. En route she defeated Casey Dellacqua, Melanie Oudin, and 2008 and 2009 French Open winners Ana Ivanovic and Svetlana Kuznetsova, respectively. She secured a place in the semifinals by eliminating the German tenth seed Angelique Kerber, her first win over a current top-10 player. In the semifinals, she overcame the reigning US Open champion and 2010 French Open finalist Samantha Stosur to reach her first Grand Slam singles final opposite Maria Sharapova. Errani lost in the final. However, her progress in this tournament helped her achieve the no. 10 ranking.
In addition to her singles wins, Errani also won six doubles titles with Roberta Vinci including the 2012 Mutua Madrid Open, the 2012 Internazionali BNL d'Italia, and the 2012 French Open. She and Vinci also made the finals of the 2012 Sony Ericsson Open and the 2012 Australian Open.
At Wimbledon, Errani lost in the third round to Yaroslava Shvedova, suffering the humiliating loss of the first Golden Set (i.e. a set in which every point is won by the same player) in the women's tennis open era, and second ever recorded. In the month of July, at the Italiacom Open 2012, Errani, without losing a set, won her fourth title of the year, the sixth in her career. She defeated the Czech Barbora Záhlavová-Strýcová (seeded eighth) in the final. Errani then lost in the first round of the singles competition at the 2012 Summer Olympic Games in London, as well as the first round of the mixed doubles (with Andreas Seppi). However, she and Roberta Vinci reached the quarter-finals of the women's doubles.
She then played the 2012 Rogers Cup, where she lost in the third round to eventual finalist Li Na. She then lost to Venus Williams in the third round of the Western & Southern Open. She then played the New Haven Open as the fourth seed. She reached the semifinals by beating fifth seed Marion Bartoli. She lost in the semifinals to Petra Kvitová. At the US Open, Errani had a slow start by beating Garbiñe Muguruza Blanco in three sets. However, she easily defeated the Russians Vera Dushevina and Olga Puchkova. She lost only three games in these two rounds. In the fourth round, she defeated sixth seed, Angelique Kerber. In the quarterfinals, she defeated her doubles partner, Roberta Vinci, to come into the semifinals, where she lost in straight sets to eventual champion Serena Williams. With this result, she is the first Italian woman in the Open Era to reach the semifinals of the US Open, and the first Italian woman ever to come at least into semifinals of two different majors.
Errani partnered again with Vinci for the US Open. They were seeded second, behind the defending champions Liezel Huber and Lisa Raymond. Errani and Vinci won the US Open women's doubles final. As of result, she reached the no. 1 spot on 10 September 2012.
At the end of the year she took part in the WTA Tour Championships for the first time in her career. Here, she was defeated in straight sets by Maria Sharapova, but she beat Samantha Stosur in the following match; she lost to fourth seed Agnieszka Radwańska in a match lasting three hours and 29 minutes (the longest best-of-three-set match in WTA Championships history). With that loss, Errani did not advance beyond the round-robin stage. She finished her breakthrough year as no. 6 in the world in WTA singles rankings.
Errani started the year in the Premier event in Brisbane. In the first round, she defeated a qualifier, Olga Puchkova of Russia. She then lost to Daniela Hantuchová. Errani had better results at Sydney, where she beat Maria Kirilenko, the 14th seed, in two sets en route to the quarterfinals. However, she lost to eventual finalist, Dominika Cibulková, the 15th seed, easily. She was the seventh seed at the Australian Open, where she had reached the quarterfinals in 2012. However, she was defeated by Carla Suárez Navarro in the first round. In the doubles tournament, Errani, partnering with Vinci, won her third Grand Slam title, beating Australian wildcards Ashleigh Barty and Casey Dellacqua in the final.
She reached the final of the Open GDF Suez in Paris, losing to Mona Barthel. At the Qatar Ladies Open, she reached the quarterfinals, but she lost to Victoria Azarenka in straight sets. However, she won her third doubles title of the year, with Vinci, beating Petrova and Srebotnik in the final. One week later, she came into the semifinals of the Dubai Tennis Championship, beating Nadia Petrova in three sets. Here, she defeated her doubles partner Roberta Vinci, reaching her second singles final of the year where she lost to Petra Kvitová in three sets. At the Abierto Mexicano Telcel, Errani reached her third final of the year (the second in a row) facing Carla Suárez Navarro. She won the final in two sets, her seventh singles title.
Her next tournament was Indian Wells, where she was seeded sixth and reached the quarterfinals, where she lost to the eventual champion Maria Sharapova in straight sets. The following week, she played in Miami, where she was the eighth seed; she received a bye into the second round, and then she defeated Daniela Hantuchová and Simona Halep easily. In the fourth round, she faced Ana Ivanovic and beat her, reaching her second Premier Mandatory's quarterfinal in a row against Maria Sharapova, but for the fourth time in a row, she lost to the Russian in straight sets.
In the first week of May, her next tournament was the Mutua Madrid Open, where, defeating Urszula Radwańska, Sorana Cîrstea, Varvara Lepchenko, and Ekaterina Makarova, she reached the semifinal, her first in a WTA Premier Mandatory, where she was beaten by Serena Williams in straight sets. She reached the semifinal at Internazionali BNL d'Italia, where she was defeated by Victoria Azarenka.
As fifth seed, she played at 2013 French Open and, trying to defend the final of the last year. She defeated Arantxa Rus, Yulia Putintseva, and Sabine Lisicki to reach the fourth round, where she struggled to upset the Spanish Carla Suárez Navarro. In the quarterfinal, Errani beat the fourth seed Agnieszka Radwańska, her first win over a current top-5 player. However, in the semifinal, she lost to a perfect Serena Williams in straight sets. In doubles, with Roberta Vinci, she reached her fifth Grand Slam final, but they lost to the Russian team of Ekaterina Makarova and Elena Vesnina.
She was defeated by Monica Puig in straight sets in the first round of Wimbledon 2013, despite being seeded fifth. She reached the final in Palermo, where she was defeated by Roberta Vinci. Then she played in Rogers Cup as fifth seed, and for the first time, she reached the quarterfinals, where she was defeated by third seed Agnieszka Radwańska. In Cincinnati she lost in the third round to Roberta Vinci again, while at the US Open she suffered a tough lost in the second round to Flavia Pennetta, eventual semifinalist; in the doubles, as defending champion, she lost in the quarterfinals to Williams sisters.
In Tokyo, at the Toray Pan Pacific Open, Errani was eliminated in straight sets by Svetlana Kuznetsova, while at the China Open she defeated Kirsten Flipkens and Misaki Doi, before losing to Petra Kvitová in three sets. She was the sixth player qualified for the 2013 WTA Tour Championships for the second consecutive time. There, she was defeated by Victoria Azarenka in straight sets, after leading 5-2 and 6-5 in the first set and after having a calf injury. Then she was defeated by Li Na in two sets, after saving three match points, one of those when she was 3-5 down. Out of the semifinals, she defeated for the first time the former World n.1 Jelena Janković in straight sets.
Errani began her season at the 2014 Shenzhen Open, where she fell in the second round to American Vania King. She then travelled to Australia to compete in the Sydney International, where she reached the quarterfinals in singles, and was a finalist in doubles with Roberta Vinci, losing to Tímea Babos and Lucie Šafářová. At the 2014 Australian Open, she lost her opening match against Julia Görges of Germany. However, the doubles was completely different, as she and Vinci successfully defended their title, defeating first-time Australian Open finalists Ekaterina Makarova and Elena Vesnina of Russia in three sets to claim their fourth Grand Slam title.
The following week she managed to defend the final at the Open GDF Suez in Paris by beating Alizé Cornet, but she lost to Anastasia Pavlyuchenkova in three sets after winning the first and having a break either in the second or in the third ones. At the Qatar Ladies Open she reached the quarterfinals, losing easily to the eventual champion Simona Halep; one week later in Dubai Tennis Championship, she lost in the second round to Sorana Cîrstea for the first time in her career, after always defeating her in the previous five meetings.
In March, her next tournaments were Indian Wells and Miami, in which she lost in the third round respectively to Eugenie Bouchard and Ekaterina Makarova; because of the loss to the Russian in Miami, she left the top 10 rankings after 94 weeks from June 2012, letting the Slovakian Dominika Cibulková enter in the top 10 for the first season in her career.
In April, she played in Charleston and she reached the quarterfinals, where she was upset by the young Swiss player Belinda Bencic, wasting an opportunity to enter in the top 10 rankings again; then, she played a good tournament at Porsche Tennis Grand Prix in Stuttgart, by beating in a row Klára Koukalová, Kaia Kanepi and Carla Suárez Navarro and by advancing to the semifinals for the first time here, where she lost to the eventual champion Maria Sharapova in straight sets. In the doubles, she won the title, partnering with compatriot and friend Roberta Vinci, after beating Cara Black and Sania Mirza; her next tournament was Mutua Madrid Open, where she beat former top 10 players such like Andrea Petkovic and compatriot Francesca Schiavone, both in straight sets, but she was upset by the French Caroline Garcia in the third round. She won her third doubles title of this season in Madrid, defeating the Spanish pair Garbiñe Muguruza and Carla Suárez Navarro; one week later, she played amazingly at Internazionali BNL d'Italia, defeating Chanelle Scheepers, Ekaterina Makarova, Petra Cetkovská, upsetting World n.2 Li Na in three sets for the first time in her career, after losing the previous six meeting against the Chinese player and beating so a top 3 player for the first time in her career; she reached the final, after beating in straight sets World no.8 and former World no.1 Jelena Janković, but she was defeated by Serena Williams, also penalized by a thigh injury, which forced her to retire in the doubles final after losing four games against Srebotnik and Psechke.
As the tenth seed, she played at 2014 French Open; she beat Madison Keys in three sets, Dinah Pfizenmaier and Julia Glushko in straight sets; then, in the fourth round she ousted seventh seed from Serbia Jelena Janković, reaching here her third straight quarterfinal, where she fell quite surprisingly to the German Andrea Petkovic, who beat her in straight sets. In the doubles, she played alongside Roberta Vinci; they reached their third consecutive final, falling to Asian pair Hsieh Su-wei and Peng Shuai in straight sets.
After losing to Caroline Garcia of France in the first round of Wimbledon in the singles, Errani had a career best performance in the women's doubles, as her and Vinci won the tournament to complete a Career Grand Slam. They beat Hungary's Tímea Babos and Kristina Mladenovic of France 6–1 6–3 in 56 minutes. Upon reaching the final, Errani and Vinci reclaimed the number 1 ranking in women's doubles, after having relinquished the ranking in February to Peng Shuai of China.
Errani competed at the 2014 Gastein Ladies in Bad Gastein where she is the second seed and she reached the semifinal, defeated surprisingly by the American Shelby Rogers; she suffered early losses in Montreal and at the 2014 Western & Southern Open in the hands of German Sabine Lisicki and at the 2014 Connecticut Open in the hands of Garbiñe Muguruza in three sets; Errani's next tournament was the US Open, where she was the fourteenth seed; she faced Kirsten Flipkens and Anastasia Rodionova and defeated them in straight sets; while in the third round she beat for the first time the former world no. 1 Venus Williams with the weird result of 6-0 0-6 7-6; then, in the fourth round, she defeated Mirjana Lučić-Baroni in three sets, reaching her 6th grand slam quarterfinal appearance, in which she lost to Caroline Wozniacki pretty easily.
Errani lost to qualifier Marina Erakovic in the first round at the 2014 Toray Pan Pacific Open.
Errani began the 2015 season at the 2015 ASB Classic where she was the 2nd seed. She lost in the 1st round to Daniela Hantuchová 6-3, 6-2. Next, Errani played at the 2015 Apia International Sydney. In the 1st round, she lost to Garbiñe Muguruza 6-0, 7-5. As the 14th seed at 2015 Australian Open, Errani won her first two matches defeating Grace Min and Sílvia Soler Espinosa. She lost in the 3rd round to Yanina Wickmayer 4-6, 6-4, 6-3.
In the Fed Cup match against France, she won her match against Caroline Garcia 7-6(2), 7-5. In her second match, she lost to Kristina Mladenovic 6-4, 6-3. Errani and Roberta Vinci lost the deciding doubles rubber to Kristina Mladenovic and Caroline Garcia 6-1, 6-2. France advanced to the semifinals beating Italy 3-2. As the top seed at the 2015 Rio Open, Errani advanced to the final defeating Teliana Pereira, Lourdes Domínguez Lino, Brazilian wildcard Beatriz Haddad Maia, and 5th seed Johanna Larsson. In the final, she beat 6th seed Anna Karolína Schmiedlová 7-6(2), 6-1. This was Errani's 1st WTA singles title in two years. The following week, Errani competed at the 2015 Abierto Mexicano Telcel. Seeded 2nd, she lost in the second round to Monica Puig 6-1, 6-1. Seeded 2nd at the 2015 Monterrey Open, Errani reached the semifinals beating Lauren Davis, qualifier Tímea Babos, and 5th seed Anastasia Pavlyuchenkova. In the semifinals, she was defeated by 4th seed and eventual champion Timea Bacsinszky 6-0, 4-6, 7-6(3). Seeded 11th at the 2015 BNP Paribas Open, Errani received a bye into the 2nd round. She lost in the 3rd round to 24th seed Sabine Lisicki 6-4, 6-2. Seeded 11th at the 2015 Miami Open, Errani again received a bye to the 2nd round. She defeated Anastasia Pavlyuchenkova and 21st seed Garbiñe Muguruza to reach the 4th round where she was defeated by 27th seed Sabine Lisicki 6-1, 6-2. Meanwhile, she suspended the doubles partnership with Roberta Vinci, preferring to dedicate herself to her singles career.
Errani began her clay court season at the 2015 Family Circle Cup. Seeded 4th, she reached the quarterfinals defeating last year finalist Jana Čepelová and qualifier Sara Sorribes Tormo. In the quarterfinals, she lost to qualifier Lucie Hradecká 6-2, 6-4. A week later, she participated in the Fed Cup World Group I playoff. She beat Lauren Davis in straight sets but lost to world no. 1 Serena Williams 6-4, 6-7(3), 3-6. Then she played in Stuttgart, where she reached the quarterfinals, losing to Simona Halep, after having defeated world no. 9 Agnieszka Radwańska and Zarina Diyas.
In May, she had disappointing appearances in Madrid and in Rome, losing on both occasions in the second round to Anastasia Pavlyuchenkova and Christina Mchale, respectively. Two weeks later, she competed at the French Open, where she beat Alison Riske, Carina Witthöft, and world no. 10 Andrea Petkovic, avenging the previous year's loss. She reached the quarterfinals for the fourth consecutive time in this tournament, by defeating Julia Görges in straight sets. She ended up losing to Serena Williams in the quarterfinals in straight sets.
Errani started her year at the 2016 Brisbane International. She lost in the 1st round to 7th seed Belinda Bencic 6-1, 6-2. She then competed at the 2016 Apia International Sydney, where she reached the quarterfinals with wins over Carla Suárez Navarro and Jelena Janković. She lost in the quarterfinals to eventual champion Svetlana Kuznetsova 7-6(1), 6-0. Seeded 17th at the 2016 Australian Open, Errani lost in the first round to Margarita Gasparyan 1-6, 7-5, 6-1.
Playing in the Fed Cup tie against France, Errani lost both of her matches to Caroline Garcia 6-3, 7-5 and Kristina Mladenovic 7-6(4), 6-1. France ended up advancing to the semifinals defeating Italy 4-1. At the Dubai Tennis Championships, Errani reached the final defeating qualifier Zheng Saisai, qualifier Yaroslava Shvedova, Madison Brengle and Elina Svitolina. In the final, she beat Barbora Strýcová 6-0, 6-2 to earn the biggest singles title of her career. Seeded 16th at the 2016 Qatar Total Open, Errani lost in the 2nd round to Tímea Babos 6-4, 6-1. Errani was seeded number one at the Monterrey Open. She defeated Magdaléna Rybáriková in the 1st round 6-1, 3-6, 6-4. In the 2nd round, she was defeated by Anett Kontaveit 6-1, 6-3. Seeded 15th at the 2016 BNP Paribas Open, Errani received a bye into the 2nd round. She lost in the 2nd round to World Number 36 Lesia Tsurenko 6-4, 6-3. Seeded 14th at the 2016 Miami Open, Errani again received a bye into the 2nd round. In the 2nd round, she was defeated by wildcard Naomi Osaka 6-1, 6-3.
Errani started her clay court season at the 2016 Volvo Open where she was the 5th seed. After getting a bye into the 2nd round, she had straight set wins over Yaroslava Shvedova, 10th seed Samantha Stosur, and Yulia Putintseva. However, she lost to qualifier Elena Vesnina in the semifinals 6-4, 4-6, 6-2. Seeded 15th at the 2016 Mutua Madrid Open, Errani lost in the 1st round to compatriot Camila Giorgi 7-5, 7-5. Seeded 14th at the 2016 Internazionali BNL d'Italia, Errani was defeated in the 1st round by qualifier Heather Watson 6-4, 3-6, 6-0. The top seed at the 2016 Internationaux de Strasbourg, Errani lost in the 1st round to Monica Puig 4-6, 6-3, 6-1. As the 16th seed at the 2016 French Open Errani was upset in the first round by World Number 102 Tsvetana Pironkova 6-3, 6-2.
Errani began her grass court season by playing at the 2016 Aegon International Eastbourne where she was the 13th seed. After receiving a bye in the first round, she lost in the 2nd round to Andrea Petkovic 6-1, 3-6, 6-4. She had her best result in grand slams this year at the 2016 Wimbledon Championships. After beating Patricia Maria Țig in the 1st round, she lost in the 2nd round to Alizé Cornet 7-6(4), 7-5.
Seeded 2nd at the 2016 BRD Bucharest Open, Errani reached the quarterfinals after defeating Aleksandra Krunić and wildcard Francesca Schiavone. She lost in the quarterfinals to 7th seed and eventual finalist Anastasija Sevastova 7-6(4), 6-3. Seeded 2nd at the 2016 Swedish Open, she made it to the quarterfinals beating Çağla Büyükakçay and Viktorija Golubic. In the quarterfinals, Errani was defeated by qualifier and eventual finalist Kateřina Siniaková 7-6(2), 6-3. Ranked 25 at the 2016 Rogers Cup, Errani won her 1st round match over Canadian wildcard Aleksandra Wozniak 6-4, 7-6(4). She was forced to pull out of her second round match against 14th seed Karolína Plíšková because of a neck injury.
Errani represented her country, Italy, at the 2016 Rio Olympics. She beat Kiki Bertens and Barbora Strýcová, but fell to Daria Kasatkina in the 3rd round 7-5, 6-2. She also teamed up with fellow country woman in the doubles competition. They made it to the quarterfinals, but lost to eventual bronze medalists Lucie Šafářová and Barbora Strýcová 4-6, 6-4, 6-4.
Ranked 32 at the 2016 Western & Southern Open, Errani lost in the 1st round to World Number 33 Coco Vandeweghe 4-6, 6-3, 6-4. At the 2016 Connecticut Open, Errani was defeated in the 1st round by Ekaterina Makarova 7-5, 6-2. As the 27th seed at the 2016 US Open, Errani lost in the 1st round to American Shelby Rogers 6-4, 7-6(3).
Following her loss at the US Open, was seeded 1st at the 2016 Guangzhou International Women's Open. After beating Han Xinyun in the 1st round, she lost in the 2nd round to Viktorija Golubic 6-7(7), 6-3, 6-4. During her last tournament of the year, she lost her first round match at the 2016 Wuhan Open, losing to Barbora Strýcová 6-1, 3-6, 6-1.
Errani ended the year ranked 50.
Errani started her year at the 2017 Brisbane International. She was defeated in the 1st round by Christina McHale 6-3, 6-3. She was scheduled to compete at the 2017 Hobart International, but pulled out because of a left thigh injury. Her next tournament was the 2017 Australian Open. For the first time since the 2012 Australian Open, Errani is unseeded at a grand slam. She won her first round match against Risa Ozaki 7-5, 6-1. In the 2nd round, Errani was up against 30th seed Ekaterina Makarova. Makarova won the 1st set 6-2; she was leading 3-2 in the 2nd set when Errani retired due to a right lower leg injury.
Playing in the Fed Cup tie versus Slovakia, Errani lost both of her rubbers to Rebecca Šramková 2-6, 6-3, 6-4 and Daniela Hantuchová 6-2, 6-0. Slovakia ended up winning the Fed Cup tie versus Italy 3-2. In March, Errani competed at the 2017 BNP Paribas Open. She won her 1st round match against qualifier Mandy Minella 1-6, 6-4, 7-5. In the 2nd round, she lost to 17th seed Barbora Strýcová 6-4, 5-7, 6-2. In doubles, Errani partnered with Alicja Rosolska; they lost in the 2nd round to 4th seeds Sania Mirza/Barbora Strýcová 6-2, 6-3. At the 2017 Miami Open, Errani beat Belinda Bencic in the 1st round 6-3, 4-6, 6-3. In the 2nd round, she was defeated by 30th seed Shuai Zhang 4-6, 6-4, 7-5.
Errani began her clay court season at the 2017 Volvo Car Open. She defeated Lucky Loser Grace Min in the 1st round 6-1, 6-1. In the 2nd round, she lost to qualifier Anastasia Rodionova 6-2, 6-2. At the 2017 Copa Colsanitas, Errani reached the quarterfinals defeating 7th seed Ekaterina Alexandrova and Sachia Vickery. She lost in the quarterfinals to 3rd seed Johanna Larsson 7-5, 6-4. Playing at the 2017 İstanbul Cup, Errani crushed Hsieh Su-Wei in the 1st round 6-0, 6-1. In the 2nd round, she was defeated by 6th seed and eventual finalist Elise Mertens 7-6(3), 3-6, 6-3. Errani then had a great result at the 2017 Grand Prix SAR La Princesse Lalla Meryem. She reached the semifinals defeating wildcard Anna Blinkova, 8th seed Alison Riske, and 3rd seed Daria Gavrilova. In the semifinals, she lost to top seed and eventual champion Anastasia Pavlyuchenkova 6-4, 6-0. Nevertheless, this was Errani's best result of the year. Her ranking moved back into the Top 100 at World Number 90. At the 2017 Mutua Madrid Open, Errani lost in the 1st round of qualifying to 8th seed Pauline Parmentier 2-6, 6-2, 6-2. After Madrid, Errani received a wildcard to play at the 2017 Internazionali BNL d'Italia. She was defeated in the 1st round by Alizé Cornet 6-3, 6-4. Due to having a low ranking, Errani played qualifying at the 2017 French Open. As the top seed, she qualified for the main draw beating French wildcard Sara Cakarevic, Veronika Kudermetova, and 20th seed Nicole Gibbs. In the 1st round, she beat World Number 58 Misaki Doi 7-6(7), 6-1. In the 2nd round, she lost to 13th seed Kristina Mladenovic 6-2, 6-3.
After the French Open, Errani competed at the 2017 Bol Open where she was the 5th seed. She reached the quarterfinals beating Aleksandrina Naydenova and Olga Sáez Larra. In the quarterfinals, Errani lost to Beatriz Haddad Maia 6-1, 6-4.
Errani began her grass court season by playing qualifying at the 2017 Mallorca Open. Seeded 2nd for qualifying, she lost in the final round of qualifying to 8th seed Jana Čepelová 6-4, 6-3. However, she got a Lucky Loser spot into the main draw due to the withdrawal of Anett Kontaveit. In the 1st round, she was defeated by 6th seed, compatriot, and former doubles partner Roberta Vinci 6-2, 6-1. Seeded 7th for qualifying at the 2017 Aegon International Eastbourne, Errani lost in the 1st round of qualifying to Verónica Cepede Royg 6-1, 6-2. Ranked 76 at the 2017 Wimbledon Championships, Errani was defeated in the 1st round by Tsvetana Pironkova 6-1, 6-4.
At the 2017 Swedish Open, Errani defeated Tamara Korpatsch in the 1st round 7-6(11), 6-2. In the 2nd round, she was crushed by 3rd seed Caroline Garcia 6-1, 6-0.
Errani began her US Open series at the 2017 Citi Open. She beat Risa Ozaki in the 1st round 7-6(0), 6-2. She lost in the 2nd round to 5th seed Océane Dodin 3-6, 7-5, 6-1. On August 7, 2017, it was announced that Sara Errani will be suspended for two months due to failing a doping test. She tested positive for the prohibited substance Letrozole, which is used for the treatment of hormonally-responsive breast cancer after surgery. Errani claimed that she likely ingested letrozole by “accidentally consuming her mother's anti-cancer medication Femara” while visiting her family. As a result, she is suspended for two months, with the ban ending Oct. 2 according to the ITF. As a result of her being suspended for two months, All her results from the date of her positive out-of-competition test on 16 February until a negative test on 7 June have been annulled; all ranking points and prize money accrued in this period have had to be forfeited.
During the 2012 season, Errani became known for producing a high first-serve percentage. Having won multiple titles on clay, she is widely recognized as a clay-court specialist and is known for her use of strategy on the surface, including her tendency to position herself well and to return serves early. Being a doubles specialist as well, she is noted for her speed around the court and for hitting the ball with a lot of spin, as well as for her deep and loopy groundstrokes.
The main weakness of Errani's game is the serve. She uses an abbreviated motion and with a small stature, she is unable to hit fast serves. As of September 2017, she has only hit two aces in the entire year. Errani set the record for slowest ever serve at 49 mph.