World champion Sebastian Vettel won the Belgian Grand Prix and stretched his Formula One lead to 92 points in a Red Bull one-two finish with Australian Mark Webber yesterday.

The victory was the 24-year-old German's seventh in 12 races so far this year, with seven rounds remaining worth a maximum 175 points.

Britain's Jenson Button finished third for McLaren after starting 13th.

"Thanks you boys, what a race," Vettel whooped over the team radio after his team's second one-two of the season and his first win since Valencia in June.

Vettel, who now has 259 points to Webber's 167 after his 17th career win, led from pole position with serious doubts about the durability of his car's tires after both Red Bulls suffered heavy degradation in qualifying.

In the end the fears proved groundless, or at least manageable, despite Vettel's compatriot Nico Rosberg storming into the lead at the start in his Mercedes before Vettel overtook on the third lap.

"It was more management than usual but the car worked brilliantly," said Vettel. "I enjoyed every lap today ... if the car does what you want it to do, this place is really fun.

"We had reason to be confident (about the tires). Otherwise the alternative would have been to change the set-up and start from the pit lane."

Ferrari's Fernando Alonso, who finished fourth, looked a real threat before fading.

McLaren's Lewis Hamilton, last year's winner, crashed heavily at Les Combes on the 13th of 44 laps at the 7-kilometer Spa-Francorchamps circuit while challenging for fourth.

Hamilton was unhurt but the incident brought out the safety car while debris was cleared.

Seven-time champion Michael Schumacher, the sport's most successful racer, celebrated the 20th anniversary of his Formula One debut at Spa with a fighting fifth place after starting in last position.

Rosberg was sixth, ahead of compatriot Adrian Sutil for Force India and Ferrari's Brazilian Felipe Massa in eighth.

Renault's Russian Vitaly Petrov was ninth and Venezuelan Pastor Maldonado collected his first point in Formula One for Williams in 10th.