A clay court is one of many different types of tennis court. Clay courts are made of crushed shale, stone or brick. The French Open uses clay courts, making it unique among the Grand Slam tournaments. Clay courts are more common in Continental Europe and Latin America than in the United States, Canada or Britain. Two types exist: red clay, the more common variety, and green clay, also known as "rubico", which is a harder surface. Although less expensive to construct than other types of tennis courts, the maintenance costs of clay are high as the surface must be rolled to preserve flatness. The water content must also be balanced; green courts are often sloped in order to allow water run-off.
Clay courts favor the "full western grip" for more topspin. "Clay-courters" generally play in a semicircle about 1.5 to 3 metres (5 to 10 feet) behind the baseline.
Clay courts are considered "slow", because the balls bounce relatively high and more slowly, making it more difficult for a player to deliver an unreturnable shot. Points are usually longer as there are fewer winners. Therefore, clay courts heavily favor baseliners who are consistent and have a strong defensive game, which has allowed players such as Rafael Nadal, Björn Borg, Chris Evert, and Justine Henin to find success at the French Open.
Clay court players use topspins to throw off their opponents. Movement on gravel courts is very different from movement on any other surface. Playing on clay often involves the ability to slide into the ball during the stroke, as opposed to running and stopping like on a hard or grass court. Players who excel on clay courts but struggle to replicate the same form on fast courts are known as clay-court specialists.
Clay courts are unique in that the ball bounce leaves an impression in the ground, which can help determine whether a shot was in or out. Critics of red clay courts point to the constant need to wet them down, problems renewing the surface if it dries out, and the damage caused to clothing and footwear through stains. All clay courts, not just red clay, tend to cause a build-up of clay on the bottom of the shoes of the players, needing constant removal.
Almost all red "clay" courts are made not of natural clay but of crushed brick that is packed to make the court. The crushed brick is then covered with a topping of loose crushed particles. This type of surface does not absorb water easily and is the most common in Europe and Latin America. The French Open is played on red clay courts at Stade Roland Garros. True natural clay courts are rare because they take two to three days to dry. A good example of natural red clay can be seen at the Frick Park Clay Courts in Pittsburgh, a public facility of six red clay courts that has been in continual use since 1930.
A crushed brick surface was introduced by a British firm, En Tout Cas, in 1909, to address the drainage problem of the clay surface. En tout cas, also known as "fast-dry", or "continental clay", court surfaces spread through Europe in the 1920s. An en tout cas court plays similarly to natural clay despite its considerably more granular appearance. The crushed brick surface allowed more water to run through the surface of the court drying the surface more quickly after a rain. In France, Spain and Italy "fast-dry" surfaces were generally shallower, consisting of powdered brick or red sand, making these courts appear more like natural clay surfaces.
Green clay, also called rubico and the brand name Har-Tru, is similar to red clay, but is made from crushed basalt rather than brick, making the surface slightly harder and faster. Green clay is packed to make the subsurface. It is then covered with a topping. These clay courts can be found in all 50 of the United States but are located primarily in the Eastern and Southern states.
There is one WTA tournament played on green Har-Tru clay courts, the Volvo Car Open in Charleston, South Carolina.
Rafael Nadal, winner of nine French Open men's singles titles is noted for his success on clay; since his debut in 2005, he has only lost twice at the tournament – in 2009 and 2015. Nadal holds the record for the longest winning streak by any male player on a single surface since the tennis open era began in 1968: 81 clay court wins between April 2005 and May 2007.
Guillermo Vilas and Rafael Nadal hold the record for most titles won on clay in the open era with 49 trophies. Vilas won one French Open while Nadal won 9. Thomas Muster is also considered a successful clay court player; although he only won the French Open once, 40 out of his 44 career singles titles were won on clay.
The most successful currently active female player on clay is Serena Williams, who won the French Open thrice, in 2002, 2013 and 2015. In 2013, Williams went undefeated throughout the clay court season, winning five titles on the surface.
Justine Henin and Monica Seles hold the record for the number of consecutive French Open titles won at three (1990–1992 for Seles and 2005–2007 for Henin). In the pre-open era this feat was first achieved by Helen Wills Moody (1928–1930) and followed by Hilde Krahwinkel Sperling (1935–1937).
Chris Evert holds the record for longest winning streak on clay for either gender in the open era: from August 1973 to May 1979, she won 125 consecutive clay court matches. During this time Evert skipped three editions of the French Opens (1976–78), to participate in World Team Tennis. She also has the highest career win percentage on clay courts (94.28%) during the open era.
A clay-court specialist is a tennis player who excels on clay courts.
Due in part to advances in racquet technology, today's clay-court specialists are also known for employing long, winding groundstrokes that generate heavy topspin, strokes which are less effective when the surface is faster and the balls don't bounce as high. Clay-court specialists tend to slide more effectively on clay than other players. Many of them are also very adept at hitting the drop shot, which can be effective because rallies on clay courts often leave players pushed far beyond the baseline. Additionally, the slow, long rallies require a great degree of mental focus and physical stamina from the players.
The definition of "clay-court specialist" has varied, with some placing players such as Thomas Muster, Gustavo Kuerten, and Juan Carlos Ferrero in that category, even though these players have won tournaments (including Masters Series events) on other surfaces. However, since these players won major titles only at the French Open, they are sometimes labeled as such. Other players, such as Sergi Bruguera, Albert Costa and Gastón Gaudio were French Open champions who won all or very nearly all of their career titles on clay. Among female players, there have been very few whose best results were confined exclusively to clay. Virginia Ruzici, Anastasia Myskina, Iva Majoli, Sue Barker, Ana Ivanovic, Francesca Schiavone and Garbiñe Muguruza are the only female players to have won major titles at only the French Open since the beginning of the open era.
Increasingly, clay courters have attempted to play better on other surfaces with some success. Ferrero reached the US Open Final in 2003, the same year he won the French Open, and has also won hardcourt tournaments. Nadal was considered a clay court specialist until a string of successes on other surfaces, including completing a career grand slam, led to a broadening of his reputation, while Muguruza reached the 2015 Wimbledon final the year before she won the French Open.
The professional clay court season comprises many more tournaments than the brief grass court season, but is still shorter than the hard court seasons. There are three distinct clay court seasons during the year.
The first is the winter clay swing in South America that occurs primarily in February after the Australian Open and before the Indian Wells Masters. The ATP has four tournaments in this swing, while the WTA only has one, the combined ATP/WTA tournament in Rio de Janeiro.
The second is the long spring clay season that starts in the Americas before moving to mainland Europe and Morocco leading up to the French Open. It is usually played over two months in April and May after the Miami Open concludes. Unlike the other two clay seasons, for the most part, this swing does not share the majority of its time with simultaneous hard court tournaments.
The third is the brief summer clay season that takes place after Wimbledon. It is entirely in Europe, and usually takes place in July. Near the end of the swing, it competes with the beginning of the US Open Series.