1991 Australian Grand Prix

In the torrential rain (which had been falling since halfway through the Group A touring car support race earlier in the day), the race started mostly without incident. Riccardo Patrese lost two places at the start and emerged behind Jean Alesi's Ferrari but there were no accidents in the first few laps. However, as the race continued into lap 3 Gerhard Berger, unseen by the television cameras, ran wide which allowed Nigel Mansell to move up to second position, but rejoining in third. Mansell then proceeded to quickly close the gap to Ayrton Senna in first place. But by lap 5 the incidents began to occur which would affect Mansell's ability to pass Senna. This was because so many yellow flags were being displayed by the marshals around the extremely wet circuit. On lap six Mansell moved alongside Senna on the Brabham Straight but quickly saw a wave from a marshal, who was leaning out from the barriers, to warn of wreckage ahead. Nicola Larini's Modena-Lamborghini had crashed on the straight and was lying across the track. Mansell had to abandon his line and rejoin the racing line behind Senna, who had also had to avoid Jean Alesi's stricken Ferrari, which had also crashed yards after Larini on the other side of the road, as did Schumacher's Benetton who also spun off on the side of the road.

Pierluigi Martini's Minardi car aquaplaned on the Brabham Straight on lap 10, which sent his car straight into the right hand wall and rebounded to the other side of the track before eventually stopping out of the drivers' way. This indicated that the rain was beginning to fall even harder, and more torrential than before. On lap 14, Mauricio Gugelmin's Leyton House was involved in a heavy crash trying to pass the Tyrrell of Stefano Modena going through turn 15. He lost control in the right hand turn and hit the inside wall of the pit lane entrance at the turn 16 hairpin with such speed, he became airborne. Two track marshals suffered minor injuries from flying debris.^[5]

Riccardo Patrese was struggling with his car because a front wing, from another car, got stuck towards the front of his undertray. This was spotted by James Hunt in the BBC race commentary, although Murray Walker had suggested earlier that it was the undertray that was loose.^[6] Mansell then, as a result of the increasing downpour, spun off on the start of lap 16 on the Wakefield Road straight, before turn 3, having "instantly gone out of control" according to Mansell himself.^[7] The torrential downpour also made Michele Alboreto spin out of the race on lap 15 as well as Modena, although he continued. Nelson Piquet also spun at the high-speed Stag turn but was able to recover and he continued as well.

Gerhard Berger spun off at the end of lap 16 having just recovered from an earlier spin at the Malthouse Corner moments before. Murray Walker said that the weather was becoming worse and the rain was lashing down on the start/finish line. Just after this happened Senna drove onto the start/finish straight and gestured to the race officials, as he went past, to try to get the race stopped.^[8] Moments later, with Senna on lap 17, the race was finally stopped. By the end of lap 16 the race order actually was Senna in 1st from Piquet, Morbidelli, de Cesaris, Zanardi and Modena.^[9] However, the race officials decided to count back to lap 14 despite the 1991 ruling that early race stoppages should have been counted back one lap. This incident was similar to the controversy of the 2003 Brazilian Grand Prix, where computers finalising the race concluded the result a lap too early.

There were attempts to restart the race from the officials, who showed their determination to do so by ordering the 10-minute warning board to be displayed to the drivers and teams to indicate a race restart.^[8] But after serious protests from Senna and Riccardo Patrese (who stormed up to the race stewards to argue against a restart), the race was finally abandoned for good. Roland Bruynseraede eventually waved the red flag to indicate the stoppage to the spectators, drivers and teams.^[8] As a result, Senna was declared the race winner from Mansell and Berger.^[10]

The podium ceremony only had Ayrton Senna and Gerhard Berger present because Nigel Mansell was sent to hospital after the injuries he sustained in his crash on lap 16. When interviewed by Jackie Stewart in the post-race press conference, Senna stated:

I don't think that was a race, it was just a matter of staying on the circuit, and there was no point to try to go quick at all. It was impossible! We had a race, a very bad one, here a couple of years ago and then was impossible [in reference to the 1989 Australian Grand Prix, which was run under identically treacherous wet conditions] and today was even worse! There was even more water on the back straight.^[7]

Senna and Berger both revealed at the press conference that they would not have started the race if this race did not determine the Constructor's Championship, as the McLaren and Williams teams both went into this race with a chance of winning the championship. When Stewart asked him if they should start a race if ever faced with those type of wet conditions in the future, Senna's reply was a firm "No, they should not start the race", though he understood the pressure that was on the officials and teams to start. He then added that the officials should not be held solely responsible as the drivers, including himself, chose to get in their cars and start the race so they should be held equally responsible.

Nigel Mansell, after being helped from his Williams-Renault commented that "everything was ok other than it was a complete joke, I mean there was debris all over the place. I've got a headache like there's no tomorrow, so I've probably had a little bit of a concussion".^[7] He also made reference to the fact that "there was a truck down the straight" as well as four cars and, as a result, the race should have had 10 laps to be stopped.^[7]

With less than seventy-five percent of the race distance being completed, half the usual world championship points were awarded, the first time this had happened in Formula One since the wet 1984 Monaco Grand Prix had been stopped just before half distance. Senna and Berger's result was enough for McLaren to win the 1991 World Constructors Championship by 14 points over Williams. This was McLaren's seventh constructors championship, and their fourth and last championship won with engine partners Honda.

Pos	No	Driver	Constructor	Tyre	Laps	Time/Retired	Grid	Points
1	1	Ayrton Senna	McLaren-Honda	G	14	24:34.899	1	5
2	5	Nigel Mansell	Williams-Renault	G	14	+ 1.259	3	3
3	2	Gerhard Berger	McLaren-Honda	G	14	+ 5.120	2	2
4	20	Nelson Piquet	Benetton-Ford	P	14	+ 30.103	5	1.5
5	6	Riccardo Patrese	Williams-Renault	G	14	+ 50.537	4	1
6	27	Gianni Morbidelli	Ferrari	G	14	+ 51.069	8	0.5
7	21	Emanuele Pirro	Dallara-Judd	P	14	+ 52.361	13
8	33	Andrea de Cesaris	Jordan-Ford	G	14	+ 1:00.431	12
9	32	Alessandro Zanardi	Jordan-Ford	G	14	+ 1:15.567	16
10	4	Stefano Modena	Tyrrell-Honda	P	14	+ 1:20.370	9
11	12	Johnny Herbert	Lotus-Judd	G	14	+ 1:22.073	21
12	22	JJ Lehto	Dallara-Judd	P	14	+ 1:38.519	11
13	9	Michele Alboreto	Footwork-Ford	G	14	+ 1:39.303	15
14	15	Maurício Gugelmin	Leyton House-Ilmor	G	13	Accident	14
15	10	Alex Caffi	Footwork-Ford	G	13	+ 1 lap	23
16	24	Roberto Moreno	Minardi-Ferrari	G	13	+ 1 lap	18
17	8	Mark Blundell	Brabham-Yamaha	P	13	+ 1 lap	17
18	26	Érik Comas	Ligier-Lamborghini	G	13	+ 1 lap	22
19	11	Mika Häkkinen	Lotus-Judd	G	13	+ 1 lap	25
20	16	Karl Wendlinger	Leyton House-Ilmor	G	12	+ 2 laps	26
Ret	23	Pierluigi Martini	Minardi-Ferrari	G	8	Spun off	10
Ret	19	Michael Schumacher	Benetton-Ford	P	5	Spun off	6
Ret	28	Jean Alesi	Ferrari	G	5	Accident	7
Ret	34	Nicola Larini	Lambo-Lamborghini	G	5	Spun off	19
Ret	25	Thierry Boutsen	Ligier-Lamborghini	G	5	Accident	20
Ret	3	Satoru Nakajima	Tyrrell-Honda	P	4	Spun off	24
DNQ	30	Aguri Suzuki	Lola-Ford	G
DNQ	7	Martin Brundle	Brabham-Yamaha	P
DNQ	35	Eric van de Poele	Lambo-Lamborghini	G
DNQ	29	Bertrand Gachot	Lola-Ford	G
DNPQ	14	Gabriele Tarquini	Fondmetal-Ford	G
DNPQ	31	Naoki Hattori	Coloni-Ford	G
Source:[10][11]

Drivers' Championship standings Pos Driver Points 1 Ayrton Senna 96 2 Nigel Mansell 72 3 Riccardo Patrese 53 4 Gerhard Berger 43 5 Alain Prost 34 Source:[12]

Constructors' Championship standings Pos Constructor Points 1 McLaren-Honda 139 2 Williams-Renault 125 3 Ferrari 55.5 4 Benetton-Ford 38.5 5 Jordan-Ford 13 Source:[12]

• Note: Only the top five positions are included for both sets of standings.
• Bold text indicates the 1991 World Champions.