Jenson Button claimed his second win this year on Sunday when he drove to a comprehensive victory in a drama-packed Belgian Grand Prix at Spa-Francorchamps, while Australia's Mark Webber finished sixth.

The other Australian in the race, Torro Rosso driver Daniel Ricciardo, came in ninth.

Button, starting from the eighth pole position of his career and his first for the McLaren team, produced a consummate display of dominant driving from start to finish for the 32-year-old Briton to claim the 14th win of his career.

His victory was his first since the season-opening race in Australia and came in his 50th outing for McLaren and 220th overall as Formula One resumed after a month off for the traditional European summer break.

Button, the 2009 champion, came home 13.624 seconds ahead of second-placed defending champion German Sebastian Vettel of Red Bull with Finn Kimi Raikkonen of Lotus completing a podium of champions by coming home third.

Championship leader Spaniard Fernando Alonso of Ferrari crashed out of the race at the first corner where he was he was an innocent victim of a multiple collision triggered by aggressive driving by Frenchman Romain Grosjean in the second Lotus.

Grosjean swerved into Briton Lewis Hamilton of McLaren causing a pile-up that eliminated both drivers, along with Alonso and Mexican Sergio Perez of Sauber.

This gifted Red Bull men Vettel and Australian Mark Webber a perfect opportunity to close ground in the title race.

Webber finished sixth behind a dazzling display by German Nico Hulkenberg, who was fourth for Force India, and Brazilian Felipe Massa, of Ferrari.

Alonso said he felt fortunate to have escaped serious injury when he was almost struck by Grosjean's airborne Lotus.

"I'm disappointed because of the points lost, but I'm also lucky that I can be in the car in five days at Monza because - looking at the images - we were turning in so you could have a problem with your hands or even your head because Grosjean's car was so close," said Alonso.

"I think we broke everything on top of the car. It was lucky in that aspect."

Grosjean was banned for one race after causing the pile-up.

"I honestly thought I was ahead of him (Hamilton) and there was enough room for both cars," Grosjean said.

"I didn't try deliberately to try and squeeze him or anything like that. The first corner situation obviously isn't what anyone would want to happen."

Grosjean misses the Italian GP at Monza on September 9.

"When your life is all about racing, not being allowed to attend an event is probably one of the worst experiences you can go through," Grosjean said. "I can only say that today is part of a process that will make me a better driver."

Michael Schumacher, in his 300th Grand Prix and back at his favourite circuit where he made his debut in 1991, finished seventh for Mercedes ahead of Jean-Eric Vergne and his Toro Rosso teammate Ricciardo with Briton Paul Di Resta taking the final point in 10th place in the second Force India.

Vettel's opportunism saw him rise to second behind Alonso in the drivers' standings with 140 points to the Spaniard's 164, while Webber (132) dropped back to third ahead of Raikkonen (131).