An otherwise quiet Italian GP burst into life as Lewis Hamilton and Oscar Piastri collided at the second chicane.
Hamilton made a good switchback move out of the first corner to get alongside the Australian heading into the Roggia chicane.
The Mercedes man, however, drifted across the road and hit the McLaren, causing damage and he was penalised five seconds as a result by the stewards.
Piastri was forced to pit with front wing damage due to the incident while Hamilton got away without any damage in a very fortunate twist for the seven-time world champion.