Lewis Hamilton keeps Italian GP Win

Italian Grand Prix 2015: Nothing- not even belated stewards' investigations can stop Hamilton

Otherwise dreary race ends with confusion as Briton is called to the stewards for having illegal tyre pressures, but his win is later allowed to stand

Lewis Hamilton crosses the finish line to win the Italian GP.

Lewis Hamilton dominated at Monza to win by 25 seconds, with Sebastian Vettel second and Felipe Massa third as Nico Rosberg was forced to retire with two laps to go, but a tyre pressure issue with both Mercedes has put celebrations on hold.

Hamilton's seventh victory this season puts him 53 points ahead of team-mate Nico Rosberg as the German retired.

Mercedes were investigated on the grounds the tyres were below the minimum permitted pressure.

But the stewards allowed Hamilton to keep his victory after ruling Mercedes had followed safe operating procedures.

Fans poured out in numbers to celebrate Vettel

Ferrari's Sebastian Vettel was second as Rosberg suffered an engine failure with three laps to go.

Hamilton survived a scare in the final laps when his team told him he had to drive flat out but not what the problem was.

It seems Mercedes were trying to get Hamilton to build a lead of more than 25 seconds in case of a penalty for the tyre pressure, which was 0.3psi lower than the minimum amount specified by Pirelli on safety grounds.

Hamilton crossed the line exactly 25.0 seconds ahead of Vettel.

Rosberg's left-rear tyre was also found to be below the required pressure - by 1.1psi in his case.

Williams's Felipe Massa fended off a late attack from team-mate Valtteri Bottas to take the final podium place.

Italian Grand Prix result1.      Lewis Hamilton (Mercedes)2.     Sebastian Vettel (Ferrari)
3.     Felipe Massa (Williams)
4.     Valtteri Bottas (Williams)
5.     Kimi Raikkonen (Ferrari)
6.     Sergio Pérez (Force India)
7.     Nico Hülkenberg (Force India)
8.    Danny Ricciardo (Red Bull)
9.     Marcus Ericsson (Sauber)10.Daniil Kvyat (Red Bull)