1990 Portuguese Grand Prix

The Friday morning pre-qualifying session produced a similar result to the previous two races, with the same four cars pre-qualifying, albeit in a slightly different order. Olivier Grouillard was fastest for the third time in a row in the Osella, half a second ahead of the AGS of Yannick Dalmas. Now a regular pre-qualifier after the disastrous period with the Subaru engine, Bertrand Gachot was third fastest in the Coloni, nearly a second ahead of Gabriele Tarquini in the other AGS.[3]

This left the now-usual trio missing out on pre-qualification. The two EuroBruns of Robert Moreno and Claudio Langes were again fifth and sixth, with Langes more than two seconds slower than his team-mate as the team began to lose touch with their rivals. The Life team had finally abandoned their unreliable and vastly underpowered W12 engine, and had fitted the L190 with a well-used Judd CV V8. It had taken ten days to modify the chassis, and the car was now 80 kg lighter. But the engine cover now did not fit properly, and it flew off on Bruno Giacomelli's shakedown lap, halfway through the session. It was slightly damaged and the team had no replacement, so no further running was possible.[4]

Tyrrell's Satoru Nakajima qualified 20th but withdrew due to influenza after crashing in the Sunday morning warm-up session. The grid was adjusted accordingly, although only 25 drivers started as no non-qualifier was reinstated.

At the start, with both Ferraris on the front row (Mansell on pole, Alain Prost second), Mansell got too much wheelspin and slid across the track towards Prost, who had to avoid being shunted into the pitwall. All of this allowed the McLarens of Ayrton Senna and Gerhard Berger to slip past Mansell and Prost to make it a McLaren 1–2 with Senna leading into the first corner. After all the mid race tyre stops, it was Senna who emerged as the race leader, followed by Mansell, Berger, and Prost. A few laps later Mansell had caught Senna and passed him into turn one (Senna letting him through, unlike the year before when they collided).

On lap 52, race leader Nigel Mansell was attempting to lap the Ligier JS33B of Philippe Alliot when the Frenchman stuck to the racing line by driving inches in front of Mansell into the inside of "Curva 2" corner. However, the right rear wheel of his car hit the left front of Mansell's Ferrari and Alliot was sent spinning into the Armco barrier. Mansell came out unscathed from this incident, and eventually won the race which was stopped early due to an accident between Suzuki and Caffi.

Ferrari announced that Jean Alesi would partner Alain Prost for 1991. Alesi was reported to have already signed a contract with Williams, but changed his mind when Ferrari showed an interest, feeling that this would give him a better chance of winning a championship.