Lewis Hamilton's aggressive driving style may have resulted in the puncture that cost him a third successive Grand Prix victory in Hungary.

It emerged today that an examination of Hamilton's front left tyre that suddenly deflated two corners into the 41st of 70 laps of the Hungaroring revealed several 'flat spots', caused when a driver brakes too hard and rubber is worn away as the car skids.

It is thought that a stone could have cut into a part of the tyre weakened by one of these flat spots. And had Hamilton not lost vital time having to go to the pits for a change of wheels, he would have been in second place and in perfect position to benefit when the Ferrari engine of race leader Felipe Massa blew up three laps from the end.

Instead, it was Hamilton's McLaren Mercedes team- mate Heikki Kovalainen who became the 100th different winner of a Formula One Grand Prix ahead of Toyota's Timo Glock, reigning world champion Kimi Raikkonen in the second Ferrari and Fernando Alonso in a Renault.

Massa's misfortune, made worse by the way he dominated the 11th round of the title chase after a brilliant overtaking move on pole-sitter Hamilton going into the first corner, means the Brazilian has dropped from second to third place in the championship.

"We did a perfect job, and then the engine just gave way," said a dejected Massa. "It was a very strange feeling, the engine breaking in such a very big way. Unfortunately this is part of our sport."

Despite trailing home fifth, Hamilton's lead is extended from four to five points with Raikkonen now taking up the pursuit. But if the 23-year-old is to maintain his advantage he may have to start treating his tyres with a little more respect.

Hirohide Hamashima, director of development for Bridgestone who supply tyres to all the teams, revealed Hamilton's failed tyre was being flown to the company's headquarters in Japan.

Hamashima said: "We have not found the actual cause but there is a high possibility of a puncture. We could not see any debris on the tread surface, although we could not analyse the shoulder area because Lewis ran half of a lap with a depressed front tyre and the sidewalls were badly damaged. So the possibility is of a side cut."

Significantly, Hamashima added that such a cut could have been made in one of the areas where Hamilton had flat spotted. He said: "Lewis made many flat spots. When there is a flat spot, it means there is a very thin shoulder area close to the ground. So maybe a sharp stone touched the sidewall, meaning there was a possibility to cause a puncture."

Hamilton, chasing a hat-trick of wins following his dominating drives in Britain and Germany, was philosophical about the result. He said: "It was probably one of my worst races, but we've come away still looking pretty good.

"At least I scored four points and maintained my lead in the championship so I can't complain." Kovalainen's maiden victory came in his 28th Formula One race, and no subsequent win is likely to be as fortunate.

The 26-year-old Finn, whose contract with McLaren was extended for another season over the weekend, admitted: "We had a little bit of luck on our side, but it doesn't feel any worse for that.

"The team knew the potential was there but we just haven't been able to nail it on a Sunday."

McLaren chief Ron Dennis celebrated Kovalainen's win on the team radio, telling his driver on his slowing down lap: "Welcome to the world of winning."

The next race is the European Grand Prix on the new street circuit at Valencia in Spain.

By then, teams should know the result of an investigation into a series of flash fires in the pit lane in Hungary. Cars belonging to Williams, Honda and Torro Rosso caught alight during refuelling, though action by mechanics wielding fire extinguishers prevented serious blazes.