Lewis Hamilton
Hamilton and Mercedes under investigation after win at Monza.Getty

Lewis Hamilton has won the Italian Grand Prix after Mercedes were cleared of breaking tyre pressure rules.The British driver briefly faced the possibility of a time penalty as an investigation was launched after his victory when it was found his left rear tyre was below the minimum permitted pressure level outlined by the FIA.

But following the stewards inquiry, Hamilton and were cleared after ruling Mercedes had sufficiently followed safety regulation, confirming his seventh win of the season. Hamilton tightened his grip on the world title, extending his lead over Mercedes teammate Nico Rosberg, after the German was forced to retire with just three laps remaining. The reigning champion now boasts a 53 point lead after comfortably maintaining his lead over second placed Sebastian Vettel at Monza.

Hamilton faced scrutiny after his left rear tyre was found to be found to be 0.3psi under required the mark. Rosberg was also under investigation, after his same tyre was found to be 1.1psi under.

Joe Bauer, the FIA's technical delegate, said: "The measured minimum tyre starting pressure of the left-hand rear tyre of car 44 (Hamilton's) was 0.3 PSI below the specified minimum tyre starting pressure and the measured minimum tyre starting pressure of car number 06 (Rosberg's) was 1.1PSI below the specified minimum tyre starting pressure. I am referring this matter to the stewards for their consideration."

When asked by BBC Sport if Mercedes knew if they had gone below the minimum tyre pressure, team boss Toto Wolff said: "No because we measure them with Pirelli. At the moment we have no detail what is going on."

During his post-race press conference, Hamilton added: "Not really no. I wasn't aware of it."

Rosberg failed to finish the raise due to engine trouble as Hamilton cruised to his seventh win of the season. Felipe Massa crossed the finish line in third ahead of Williams driver Valttteri Bottas in fourth.