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.

[1][2] 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.

Argentine Oscar Larrauri had returned to EuroBrun for whom he raced in 1988, replacing Swiss driver Gregor Foitek, but with no improvement down in eleventh.

Second was a surprise as Ferrari's Gerhard Berger joined Senna on the front row, whilst his teammate Nigel Mansell was third.

Prost was only 4th, some 1.79 seconds slower than his Brazilian teammate, publicly complaining all weekend of a down on power engine compared to Senna's.

Prost would later say that while handling and grip were significantly improved, the down on power engine remained and despite the same wing settings he still could not match his teammate for straight line speed.

[4] Senna led from the start and built up a small lead over Berger, while Mansell (whose 'development' V12 engine was not revving right) and especially Prost struggled to stay in touch.

The Williams' pair of Boutsen and Patrese, having found the limits of the older FW12 model, were circulating in 4th and 5th places but at no stage threatened the leaders.

On lap 44 the roar of the crowd told the story as the V10 Honda in Senna's McLaren comprehensively blew up going into the Parabolica, dumping its oil onto the rear tyres and sending Senna into a gentle spin and retirement, handing Prost the lead which he held to win his first Italian Grand Prix since 1985.