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 Sunday.

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 tyres 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 tyres). Otherwise the alternative would have been to change the set-up and start from the pit lane," he added.

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

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

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

Seven times 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.

Webber made a shocking start from third place, wrestling with the anti-stall device as others roared past, but escaped the early mayhem triggered by Brazilian Bruno Senna on his Renault debut.

"It was probably one of our best results ever as a team," said the Australian.

Senna, the reserve called up as a replacement for dropped German Nick Heidfeld, had qualified an impressive seventh but picked up a drive-through penalty for causing a collision and ended up 13th.

McLaren's Lewis Hamilton crashed out of the Belgian Formula One Grand Prix Sunday, bringing out the safety car.

The Briton, winner at Spa last year, speared into the metal barriers at Le Combes after trying to pass Sauber's Japanese Kamui Kobayashi for fourth place.

After a pause, the 2008 champion released the steering wheel and stepped out of the cockpit while the safety and medical cars were deployed.

The McLaren's rear left wheel touched the Sauber's front right, a contact that sent Hamilton's car careering off the track.

Hamilton had started the afternoon 88 points adrift of Red Bull's championship leader Sebastian Vettel, with seven races remaining after Spa.