The race weekend began with the debacle surrounding the events in Japan two weeks earlier where the McLaren-Hondas of Alain Prost and Ayrton Senna had taken each other out in their battle for the race lead and the World Championship with just seven laps remaining. A post-race disqualification to Senna for cutting the chicane to return to the circuit saw Prost confirmed as a triple World Champion and Senna was far from happy with FISA and in particular its French president Jean-Marie Balestre whom he accused of rigging the championship for his fellow countryman. Senna initially threatened to boycott the event and leave Formula One altogether. However, after lengthy talks with his family and McLaren boss Ron Dennis, he reluctantly showed up at Adelaide and immediately set the pace on Friday, showing he would be just as strong as ever in 1990. Prost was determined to go out on a high note in his last Grand Prix for McLaren before joining Ferrari.
Despite Prost being declared World Champion, the championship was still under a cloud as McLaren were appealing Senna' Japanese Grand Prix disqualification. Ron Dennis explained in a press conference that McLaren appealing the DQ was in no way motivated against Prost (who was leaving the team) winning the championship, it was purely from the point of view that they believed a race win had unjustly been taken away from the team (including the prizemoney as well as sponsorship bonuses from team backers such as Marlboro). The fact that the outcome might favor Senna who was staying with the team was not a factor. This meant that if Senna won in Adelaide he could still be declared champion if his disqualification from Japan was overturned. In a hearing in Paris the week after Japan, FISA had also labeled Senna as a 'dangerous driver' (citing a number of incidents involving the 1988 World Champion) and gave him a six-month suspended sentence, a decision that was met with harsh criticism from many in the F1 paddock, including rival team bosses such as Ken Tyrrell. Most agreed the collision between the McLarens, while the culmination of the growing hostility between Prost and Senna that had been building since Imola, was nothing more than a racing incident and that Senna was being harshly punished by the governing body of the sport. Dennis also claimed that the charges and subsequent Paris hearing against Senna were farcical and that the stewards report of the incident had been "badly changed" from the initial one given in Japan.
In other news, after pre-qualifying his car on the Thursday, one driver announced his retirement from Formula One on the Friday before official practice started. Italian veteran Piercarlo Ghinzani, who started his career with Osella at the 1981 Belgian Grand Prix where he finished 13th, would be driving in his 76th and last Grand Prix, coincidentally also for Osella. Ghinzani would qualify 21st for his final Grand Prix. He had only scored two points in his Formula One career when he finished 5th at the 1984 Dallas Grand Prix for Osella.
Thursday mornings pre-qualifying (the first time the F1 cars had ever been on track in Adelaide before the usual first practice session on the Friday morning) eliminated both the Zakspeed-Yamahas, making it the 16th race in succession in which Aguri Suzuki had failed to pre-qualify. This was Zakspeeds last entry in a Formula One race, providing a finishing touch for what had been a horrible season for the outfit as Suzuki had not once pre-qualified while his team mate Bernd Schneider had only pre-qualified twice in Brazil and Japan. Zakspeed were once headlined to be the next Ferrari (mainly as they were the only other team to actually use their own engines in the turbo era once Renault and Alfa Romeo pulled out at the end of 1985). This was despite the small German team not having anywhere near the resources or expertise available to the Maranello based outfit. The problem with their 1989 challenge was not the neat, Gustav Brunner designed 891, it was the Yamaha OX88 V8 engine which was found to produce only 560 bhp (418 kW; 568 PS) compared to the lower end customer Judd and Ford V8s and the Lamborghini V12 which produced 620 bhp (462 kW; 629 PS). This also left the Zakspeeds with approximately 100 bhp (75 kW; 101 PS) less than the leading engines of Honda, Ferrari, Renault and Ford.
Piercarlo Ghinzani pre-qualified in his last race while Nicola Larini and qualifying specialist Philippe Alliot both drove impressively to pre-qualify. The other driver was JJ Lehto in an Onyx. The two surprises were Michele Alboreto and Stefan Johansson, team mates at Ferrari in 1985 and 1986, who were both very disappointing and failed to pre-qualify. After taking over the second seat in the Larrousse teams Lola-Lamborghini at the German Grand Prix, Alboreto had never quite come to grips with the car and it was his second failure to pre-qualify the car after also failing in Spain. Johansson, who had finished a brilliant third three races previously in Portugal, was 5th in pre-qualifying, only 0.97 behind team mate Lehto (and 0.59 in front of the 6th placed Alboreto). All four pre-qualifiers were under Gerhard Berger's 1987 lap record which had been set in the 900 bhp (671 kW; 912 PS) turbocharged Ferrari F1/87.
Friday qualifying saw Prost pip Senna to pole, with Thierry Boutsen impressing to come within under a tenth of a second behind Senna in third. Pierluigi Martini also continued his late season qualifying form with fourth in his Pirelli shod Minardi. The positions 4th–9th were filled with Italians with Japanese Grand Prix winner Alessandro Nannini fifth, Riccardo Patrese sixth, Stefano Modena doing well to come seventh, followed by the two Dallaras of Andrea de Cesaris ahead of team-mate Alex Caffi. British driver Martin Brundle was 10th. Ferrari were all at sea even before the downpour on Sunday and were very disappointing with Berger 11th in his last race for the team before joining McLaren, and Nigel Mansell in 16th, neither driver able to find handling balance with their V12 Ferrari 640s.
Saturday was cooler, and Senna did a spectacular lap to qualify below the 1:17s, to take pole overall for the race. Prost did not improve and settled for 2nd, while Martini did an excellent lap to beat Nannini to third by just one tenth. The two Williams-Renaults were fifth and sixth with both drivers complaining of traffic on their runs, while Nigel Mansell was doing much better to qualify seventh going a second faster than he did on Friday while Berger fell to 14th. Berger was unable to better his Friday time as his car experienced engine failure on the track and he was forced to use Mansell's race car for his qualifying run which was halted when the on-board fire extinguisher was triggered (Berger could not use the spare Ferrari as it reportedly had a development engine planned for 1990 and it was strictly for Mansell's use only. Rumours had McLaren boss Ron Dennis popping his head into the Ferrari garage and jokingly telling Berger he could use the spare McLaren if he wished before he was asked to leave by Ferrari team boss Cesare Fiorio). The Dallaras were 9th and 10th on the grid with Nicola Larini in the Osella in his (and the team's) highest qualifying result in 11th.
Only 24 seconds before the end of the final qualifying session, Eddie Cheever in his Arrows-Ford caused the red flag to be shown as he had heavily crashed his car at the entrance to the pit straight directly opposite the pits. Television viewers worldwide were treated to a driver's eye view of the accident as the Arrows of Cheever and Derek Warwick were carrying forward-facing cameras for the weekend. Coming out of the final hairpin onto pit straight, Cheever ran wide and went over the curbing and hit the concrete wall that protected the grandstand from the cars, severely damaging the left front and rear of the car and leaving a large pool of oil on the racing surface as the car came to rest lying across the middle of the track. Cheever himself was unharmed; after he threw his steering wheel away in disgust he climbed from the car, ran across the track and jumped the wall into the pits.
The four that failed to qualify were Jonathan Palmer in his Tyrrell, which proved to be his last Grand Prix before being a pit lane reporter for the BBC in 1990. Luis Pérez-Sala in the Minardi who was significantly slower than team mate Martini, and the two Rials, in what was also their last race. Despite a fourth for Christian Danner at the US Grand Prix, it was not enough to save the team for next season. Bertrand Gachot and Pierre-Henri Raphanel were two seconds slower than Sala.
Sunday was cool and overcast with rain being forecast for later in the day. At the drivers meeting before the race Ligier driver René Arnoux announced his retirement from Formula One racing at the age of 41. He qualified 26th and last for what would be his 149th start in Grand Prix racing having begun his career back in 1978 with the Automobiles Martini team and a career that included teams such as Surtees, Renault, Ferrari and Ligier with 7 wins, 22 podiums 18 pole positions and 12 fastest laps. Arnoux had finished a career best 3rd in the World Championship in 1983 while driving for Ferrari.
After the morning warm-up session, the rain arrived just before the second Group A touring car support race of the weekend and an extra 30 minute session (already organised for such an occasion) was given for the teams to set their cars up for what would be a wet race as the weather forecast had the rain staying around all day. During the extra session a lot of drivers aquaplaned off the circuit, some on their out lap, notably Prost and Berger. Even rain master Senna spun his car a full 360° over the high curb on the outside of Brewery Bend, his car emerged pointing in the right direction and he powered off without hurt down the Brabham Straight. Prost and Berger, along with Nelson Piquet, Thierry Boutsen, Riccardo Patrese and Alessandro Nannini discussed not racing over safety concerns with Prost, Berger and Piquet in particular telling television interviewer Barry Sheene and a worldwide television audience that the conditions were too bad to race in. The drivers argument was that the race should be postponed as the rain was forecast to ease within a couple of hours. Officials though had other ideas.
An hour before the race the conditions significantly worsened, and Prost and Berger's proposal was being seriously considered by a lot of drivers. One driver who remained silent throughout all the impromptu drivers meetings on the grid was World Champion Ayrton Senna who had other reasons for wanting to start despite the appalling conditions (Senna was one driver who actually remained in his car the whole time). With McLaren's court action over his disqualification in Japan still pending the championship was technically not yet settled and to keep any chance of retaining his World Drivers' Championship he simply had to win the race. Senna later privately confessed to a friend that even he thought it was too dangerous to race but that he was a contracted driver and racing was what he was paid to do. He also said that championship or not, he believed Prost did the right thing by not taking the restart as he had nothing to gain by driving in such conditions. The drivers' arguments failed and it was agreed the race would go ahead. It also emerged that while still in his car Senna had been approached by Boutsen to get his thoughts about starting. Senna reportedly agreed the race should not go ahead, but he was bound by both his contract and the championship situation to start.
Inexplicably, the lights went out before the grid had even properly lined up causing some confusion at the back (Eddie Cheever had been slow away on the warmup lap and was only just coming off the Brabham Straight as the lights went green). Prost got the jump on Senna at the start, but into the first corner, Senna braked significantly later, and re-took the lead, nearly hitting the Frenchman in the process (Prost did not put up a fight). Further back, Martini fishtailed on his Pirelli rain tyres which were considered to not be as good as the Goodyear shod cars around him, and Nannini overtook him for third. Other drivers who made a good start were de Cesaris and Brundle.
On the first lap, Olivier Grouillard spun off at turn 4, nearly collecting team mate Arnoux. As the field drove round, clinging on to the road as much as possible, a lot of drivers made mistakes including Nelson Piquet and Modena. But JJ Lehto's accident just after the first chicane partially blocked the road, causing the race to be stopped. While that was happening, Prost had pulled into the pits, withdrawing because of safety, before going on to criticise the race organisers for allowing the race to have been started in the first place. Before the race had started Prost stated his intention to honour his contract and start the race, but that he would pit after one lap and retire from the race. Prost, who it was well known did not like racing a Grand Prix car in wet conditions for reasons of safety, remained true to his word and did not contest the restart, despite the best efforts of team boss Ron Dennis to persuade him to do otherwise.
As the cars waited on the grid, drivers argued whether the race should be restarted. The main drivers arguing for the race to be abandoned were Berger, Mansell, Patrese, Boutsen, Piquet and Nannini. Those arguing for the race to restart were Martini, Brundle, Jean Alesi (despite suffering from bronchitis) de Cesaris and Caffi. FOCA boss Bernie Ecclestone also pressed the race organisers to restart the race and as usual, he would get his way. Bernie also told Barry Sheene in an interview he believed Prost would take the second start (due to his McLaren being at the end of pit lane, though Prost had no intention of getting back into his car), and that he had gone around the circuit in a course car and found the conditions had 'improved', though it was argued that there was a significant difference between a slow lap in a road car and a lap at speed in a Formula One car. Through it all, Senna remained silent sitting in his McLaren. Prost later told reporters that Ecclestone had told him they had cleared the puddles from the Brabham Straight which was where most of the cars were aquaplaning, though Prost did not believe him as it was still raining at the time.
At the 2nd start, Larini stalled his Osella's Ford V8 before he even made his grid slot and was pushed off the circuit by the marshals, his race done before it started. Alesi started from the pit lane after his car stalled on the dummy-grid and he had to be pushed into pit lane to be restarted. At the front, Martini made a great a start to take advantage of the gap left by Prost's absent car to get level with Senna, but the Brazilian kept the lead by cutting across him. Everyone else kept order behind, though Nannini, despite having no one in front of him with Prost's absence, was passed by the Williams' pair only a few corners after the start.
While Senna pulled away at impressive speed (he was almost 9 seconds in front after just the first lap, though he was also the only driver who had a clear track in front of him and was not affected by almost zero visibility), the race became more of a guessing game as to who would go off. After a few laps of glory in second place where he used better visibility and less wheelspin from his less powerful Ford V8 engine to stay ahead, Martini was passed in quick succession by both Williams' and Nannini and the trio immediately started to match Senna's now more steady rather than charging pace. They quickly left the Minardi with its inferior Pirelli wets well behind. The first retirement was Arnoux after he was pushed into a spin by Eddie Cheever and was beached on a high curb, ending his career on a low. Arnoux had actually been 2nd fastest in the wet pre-race warmup behind Senna and had been confident of a good showing. Berger and Alliot then collided at the East Terrace bend, Berger taking out Alliot (though it was initially reported to be Mansell), while Derek Warwick spun into the turn 7 and 8 esses when his throttle stuck open (as seen by his onboard camera which showed Warwick lucky not to be hit by his own right front wheel after hitting the concrete wall).
Then in the space of two laps, six cars retired. Both Dallara's spun out at the same place at Brewery Bend (with Caffi appearing to have hurt his shoulder after hitting the inside wall though it was reported he had badly banged his foot), though de Cesaris was able to continue before spinning again later in the lap and beaching himself on a curb, while Mansell, Nannini, Piquet and Cheever all had off track excursions. However, the major accident was Ayrton Senna running into the back of Brundle while lapping him and Piquet, in a famous incident recorded by a rear view camera mounted on the back of the Brabham which television commentator Murray Walker described as the McLaren "bearing down on him like Jaws". Senna, who earlier had multiple spins on one lap before the pits hairpin (amazingly losing only 4 seconds in the process), was out with major front suspension damage after returning to the pits with his right front wheel missing, as was Brundle, and the Williams' of Boutsen and Patrese were one-two with Nannini still in third despite his off track excursion. Ivan Capelli also retired his March.
Five laps later, Mansell spun out at Stag Turn and then there was a major collision involving Piquet and Ghinzani. Piquet, who could see nothing but a grey wall of spray and as a consequence missed his braking markers, ran into the back of the braking Osella at speed at the hairpin at the end of the Brabham Straight and one of Ghinzani's rear tyres hit Piquet's helmet, in a scary accident, though luckily the triple World Champion was not injured. Ghinzani, who was also very lucky not to hit Martini, limped away from his broken Osella and Grand Prix racing having banged his ankle on the cars monocoque.
Following these incidents the race was a gingerly affair, with those behind the leading trio not driving to win but to stay on the circuit. The last retirement of the race was Eddie Cheever (who as it turned out was driving in his 143rd and last Grand Prix) when he spun his Arrows down the East Terrace escape road and stalled his engine on lap 42. Cheever, who earlier in his career had gained a reputation for being a good wet weather driver, had driven much of his race was a piece of another car's front wing lodged in one of the Arrows sidepods. The only major action was Satoru Nakajima, in the best drive of his career which drew praise even from those who had regularly been critical of him such as 1976 World Champion James Hunt. Nakajima set the fastest lap of the race, making his way through the field and almost catching Patrese for third, but finally settling for fourth (Nakajima had spun at the chicane on the first lap of the restart and was dead last by a long way at the end of the first lap). His drive surprised and delighted many as he had always been known to dislike street circuits and also had no like for racing in the rain. The other interest was third placed qualifier Martini who went steadily backwards to finally finish in sixth place, three laps down on Boutsen. Martini's race generally confirmed the view that while Pirelli's qualifying tyres were superior to the Goodyears, it was the opposite for both dry and wet weather race tyres with Goodyear holding a distinct advantage.
During the middle stages of the race, Nannini, who had earlier passed a spinning Patrese for second place, was able to make significant inroads into Boutsen's lead and actually got to within a second of the leading Williams. However, as seen by the television cameras, this was mainly due to his Benetton team mate Emanuele Pirro who ignored flags telling him he was about to be lapped. Pirro held Boutsen up for just over 3 laps allowing his team leader to close the gap. Boutsen eventually managed to pass the Benetton (shaking his fist in disgust soon after), while not surprisingly Pirro then moved over and let Nannini through. It mattered little though as an angry Boutsen then proceeded to drive steadily away from his 1988 Benetton team mate with Nannini unable to respond.
After two hours 70 laps had been completed out of 81, and Boutsen won his second wet race of the season followed by Nannini. Patrese finished third with Nakajima fourth having a good last race for Lotus before joining Tyrrell in 1990. Patrese said in the post-race driver interviews that in the conditions he was only driving for third place knowing that with Mansell failing to finish, this would have allowed him to pass Mansell on points and finish a career best third in the Drivers' Championship. Pirro came home fifth in his last race for Benetton and Martini eventually came sixth, 3 laps down. The remaining survivors were the March of Maurício Gugelmin and the Brabham of Stefano Modena, both of whom stayed out of trouble and kept their cars pointed in the right direction, but got no reward for their efforts.
Everyone was relieved the race went without any significant incident in such treacherous conditions.Note: Only the top five positions are included for both sets of standings.