On lap 24 of 51, the McLaren pair came to blows at the first chicane as rookie racer Piastri re-joined the Monza track alongside earlier-stopping Norris in a dice for what was then 10th position.
With Piastri on the inside at the tight first apex, the front-right of the Australian’s MCL60 glanced his team-mate's sidepod. There was no major damage and both escaped punishment from the stewards.
Nevertheless, team boss Stella branded the incident as “unacceptable”. He said: “There should never ever be contact between two McLaren cars.
“There was a contact, which doesn’t fit the way we go racing at McLaren.
“What is important is to have clear parameters as to what you deem acceptable and what you deem unacceptable. It’s not an emotion thing, it’s just like you do with other things.
“You deal with racing in a similar way. This is very clear that for any driver, there’s something bigger than them. It’s the team.”
Stella added that McLaren did not necessarily need to take urgent action in response to the bash and considered whether Piastri had misjudged emerging on colder hard tyres.
Source: Autosport