SAO PAULO, October 19- Briton Jenson Button was crowned world champion Sunday when he finished fifth in an incident-filled Brazilian Grand Prix won by Australian Mark Webber.Button, who has led the championship all season after winning the opening Australian Grand Prix in March, had started 14th on the grid, but drove with courage and determination to achieve his goal and send the Brawn GP team into wild celebration.
"We are the champions," Button sang out of key from his cockpit after crossing the finishing line and capturing the title with one race to spare.
Later the 29-year-old added: "It’s really amazing especially after the last few weeks. It was such an awesome race.
"When I first jumped in a car 21 years ago I never expected to be world champion – but we did it today."
Button’s success ensured also that the Brawn team, created out of the ashes of the defunct Honda team last winter, also clinched the constructors’ championship.
Button’s triumph as champion was a classic case of the tortoise and the hare in the second half of the season, as he survived the intensifying pressure around him.
But he continued to collect points and took the title with a solid drive in Sunday’s dramatic 71-lap race.
His tearful team boss Ross Brawn said: "It’s still got to sink in. It will take a while. It’s just special. Very special.
"All the people who couldn’t be with us, because we had to re-size the team after the winter, my thanks go to them. I hope they’ve enjoyed it because they’ve been part of what we’ve done.
"The second half of the season was hard but it was a great race today. Jenson knew what he had to do."
Button’s father John Button, who has supported his career and attended every single one of his races, said: "I’m a bit drained. The last seven or eight laps, we were all crying like little girls. I’m all washed out at the moment.
"I’ve got to accept where he is now – up there with all those great names. I haven’t got my head round it."
Button’s success delivered the 14th world championship in Formula One won by a British driver and he, individually, became the tenth British champion, but the first to triumph after leading the title race for a whole season.
Button’s great success came in his 169th Grand Prix and at the end of his ninth season in Formula One, a year when he won six of the opening seven races and then struggled to recapture that form.
Webber, in a Red Bull, won comfortably ahead of Pole Robert Kubica in a BMW Sauber and third-placed outgoing drivers’ champion Briton Lewis Hamilton in a McLaren Mercedes.
German Sebastian Vettel, in the second Red Bull, was fourth ahead of Button with Finn Kimi Raikkonen sixth for Ferrari.
Swiss Sebastien Buemi of Toro Rosso was seventh and the luckless local hero Brazilian veteran Rubens Barrichello, in the second Brawn, eighth after starting from pole position.
He suffered from heavy traffic and then a late puncture that wrecked his hopes of glory.
After Saturday’s torrential storms, the race began in dry conditions and warm sunshine, but that did not signal any reduction in the level of incident as three accidents and a fire in the pit lane lit up the opening laps.
Barrichello made a fine clean start to lead, but behind him Kimi Raikkonen attacked hard on super-soft tyres and KERS on his Ferrari, jumping to third through the Senna S curves before grazing Webber’s Red Bull.
Jarno Trulli of Toyota was also in the wars, colliding with Adrian Sutil’s Force India. Both went off and took two-times world champion Fernando Alonso out with them in his Renault.
Trulli was so furious he confronted Sutil as soon as they had climbed from their cars and the pair, with their racing uniforms and helmets on, were seen gesticulating and shouting as their cars were rescued.
All this resulted in a safety car being required and Heikki Kovlainen of McLaren, who had spun on the opening lap, was swiftly into the pits, but exited prematurely with a fuel hose still attached to his car and petrol pouring from it.
This flew into Raikkonen’s car, which briefly burst into flames as the fuel hit the exhaust system.
The safety car came in after five laps with Button benefiting from the mayhem and advancing to ninth and then to a comfortable fifth.