after his Italian Grand Prix victory on Sunday, it was confirmed that Lewis Hamilton and his Mercedes team-mate Nico Rosberg were under investigation for potentially illegal tyre pressures.

Hamilton won his seventh race of the season in Monza to seemingly stretch his championship lead over Rosberg to 53 points after the German retired with just two laps remaining, but there was confusion after the race.

Defending world champion Hamilton had been urged to pick up the pace over the radio late in the race and after finishing 25 seconds in front of Sebastian Vettel, the Briton's victory was called into question as he was informed he and Rosberg would have to face the stewards

Hamilton will now be hoping his exploits in Monza do not prove to be in vain, with disqualification a possibility.

An FIA statement said: "Monza race winner Lewis Hamilton and Mercedes team mate Nico Rosberg are under investigation by the stewards for a potential breach of the regulations regarding minimum starting tyre pressures.

"Guidelines issued by Pirelli stated that teams must start the race with tyre pressures of 19.5psi or above, however when both Mercedes were checked ahead of the start, Hamilton's left-rear tyre was found to be 0.3psi below the required mark, with the same tyre on Rosberg's car 1.1 psi under.

"The FIA also checked the starting tyre pressures on both Ferraris, but found them to be above the required value.

"Mercedes received the report from the FIA"s F1 technical delegate Jo Bauer at 1504 local time, before the chequered flag had fallen.

"The matter is now under investigation by the stewards."