Fernando Alonso won the Italian Grand Prix at Monza after passing initial leader Jenson Button on lap 38 as a result of the pit-stops.
After taking a hard-earned pole position on Saturday in his Ferrari, Alonso did not have the best getaway at the start of the race, and that allowed Button into first place in his McLaren by turn one.
Felipe Massa, who started third, challenged Alonso through the Curve Grande, while Lewis Hamilton, who started fifth and had already passed the slow-starting Mark Webber, was lurking just behind the two Ferraris.
At the second chicane Alonso had the inside line on Massa and secured second place in the braking zone. Hamilton behind attempted to follow him through past Massa, but didn't commit fully to the move.
Hamilton's front right wheel connected with Massa's left rear wheel twice with the second contact causing irreparable damage to Hamilton's front right wheel.
The McLaren driver slid into the gravel trap at the next corner and out of the race.
Up front, Button was immediately under threat from Alonso. This was not only because of Button's high downforce set-up, but because contact between him and Alonso in turn one on the first lap had damaged Button's rear diffuser.
Button was easy prey for Alonso on the straights, but he did not make any mistakes in the corners and was able to hold him off.
After 10 laps Button put in a series of quick laps and briefly broke away, but Alonso soon reeled him in again.