The 1989 Italian Grand Prix was a Formula One motor race held at Monza on 10 September 1989. It was the twelfth race of the 1989 Formula One season. Alain Prost took his fourth and final win of the season after McLaren teammate and pole-sitter Ayrton Senna suffered an engine failure with nine laps to go, thus extending the Frenchman's lead over the Brazilian in the Drivers' Championship to 20 points. Having earlier announced that he was moving to Ferrari for 1990, Prost dropped his winners' trophy from the podium into the crowd, to the severe disapproval of his team manager Ron Dennis. Gerhard Berger, the man Prost would be replacing at Ferrari, recorded his first finish of the season with second, followed by the two Williams of Thierry Boutsen and Riccardo Patrese. The final points went to Jean Alesi in the Tyrrell and Martin Brundle in the Brabham. Pre-race Before the Italian Grand Prix, Alain Prost announced that he had signed with Ferrari for the upcoming 1990 season. To the Tifosi who had previously seen Prost as the villain, he was now the hero of the crowd. It mattered not that he was still driving for McLaren, he was a confirmed Ferrari driver now and was treated as such (in previous years he had been jostled, jeered, and even pelted with tomatoes by some of the Tifosi for daring to beat the Ferraris). Prost's announcement allowed Frank Williams to re-sign Riccardo Patrese for 1990 (Prost had offers from both Ferrari and Williams). Lotus also announced at the Grand Prix that they would be using the Lamborghini V12 engine in 1990. They also confirmed that their 1990 drivers would be Derek Warwick and the teams test driver Martin Donnelly. Qualifying Pre-qualifying report For the first time in six Grands Prix, Onyx were not fastest in pre-qualifying. That credit went to Larrousse-Lola, as their cars were first and second on Friday morning, with Philippe Alliot ahead of Michele Alboreto. Third was Nicola Larini in the Osella, with Bertrand Gachot's Onyx fourth. Gachot's team-mate Stefan Johansson missed out in fifth. Sixth was the AGS of Gabriele Tarquini, with Roberto Moreno's Coloni seventh. Eighth was Larini's Osella team-mate Piercarlo Ghinzani, his eleventh pre-qualifying failure this season. As at the previous meeting, the Zakspeeds were ninth and tenth, Bernd Schneider again ahead of Aguri Suzuki. Argentine Oscar Larrauri had returned to EuroBrun for whom