Mark Webber produced a fine performance to secure his second victory of the season in the Brazilian Grand Prix, but the Red Bull man's success was overshadowed by Jenson Button securing a fifth place finish that was enough to crown him the 2009 champion.
Button's hopes of securing the title in the penultimate race of the season looked to have taken a hit when he was only able to qualify down in 14th place while team-mate Rubens Barrichello secured a popular home pole.
However, a champions drive from the Briton allowed him to come through into the points while Barrichello's title hopes vanished after a poor middle stint and a late puncture left him down in eighth place.
Sebastian Vettel – the only other man still in contention for the crown – came through from his own poor performance in qualifying to secure fourth, but the German's title hopes also ended at the penultimate event.
After the rain that had affected qualifying, race day dawned with dry conditions for the race, with the opening lap proving to be one of the most dramatic of the season.
Barrichello made a strong start from pole to lead into turn one from Webber, while Kimi Raikkonen also made a strong start to storm through to third place going into turn one. Raikkonen however would then made contact with the rear of Webber's car on the run into turn four and damaged his front wing; backing the Finn into the cars behind and setting off a chain reaction which would put three cars out of the race.
Adrian Sutil attempted to make a move on the Ferrari exiting turn five for position but in doing so, forced Jarno Trulli onto the grass. The Toyota man lost control and came back across the circuit, collecting Sutil before going into the barriers. Sutil spun off the other way and then collected the Renault of Fernando Alonso with all three drivers forced out and the Safety Car deployed.
Raikkonen pitted at the end of the opening lap, as did McLaren's Heikki Kovalainen after spinning at the start after a touch from Vettel. Kovalainen then left the pits with his fuel hose still attached, spreading fuel over Raikkonen's Ferrari as the Finn left his stall and causing a flash fire in the pitlane – although both drivers were able to continue.
Amidst the drama, Button had made a fine start to climb up to ninth, while Vettel was two places back in eleventh.
On the restart, Barrichello set about trying to pull away from Webber, Robert Kubica and Nico Rosberg, while Button quickly made his way into the points as he took eighth from Romain Grosjean exiting turn five. On the following lap, the Briton dived down the inside of Kazuki Nakajima into turn one to take seventh and then set about the Toyota of F1 debutant Kamui Kobayashi – swarming all over the rear of the Japanese driver and complaining over the radio about excessive weaving from the rookie before eventually making a move stick on the 24th lap.
Barrichello had looked comfortable out front through the early stages with a series of fastest laps but his chance of victory in the race was hit when he exited the pits after his first stop in traffic and then lost more time battling with Vettel. The time lost by the Brazilian not only allowed Webber – who had kept the gap to the lead down to two seconds – through into the lead but also allowed Kubica to get ahead when the pair had completed their stops.
Button climbed as high as second before making his stop while Vettel also got as high as second before making his first stop – with Barrichello lying third when the first stops had been completed, Button in sixth and Vettel in seventh.
Through the second round of stops, Webber maintained his lead from Kubica while further back, Vettel was able to get ahead of Button when the pair completed their final stops – leaving Vettel fifth and Button sixth.
That result would have been good enough for Button to secure the crown, but a first F1 title was secured when Barrichello was forced to pit with a puncture with eight laps to go, possibly as a result of contract from the McLaren of Lewis Hamilton – who had changed his strategy by pitting under the Safety Car at the start and then gradually climbed up the order as the race progressed.
Through the final laps, Webber maintained his lead over Kubica to secure his second career win, while Hamilton's change in strategy paid dividends as he came through from 18th on the grid to secure the final place on the podium.
Vettel took fourth – and now lies second in the championship standings as a result – while a euphoric Button claimed fifth and the drivers' title after a performance which went a long way to silencing the critics who suggested he was stuttering towards the crown, with a number of impressive overtaking moves as he worked his way through the pack to secure the points needed to put him out of reach.
Raikkonen took sixth for Ferrari ahead of Sebastien Buemi, who carried his strong qualifying form into the race to take points for Toro Rosso, while a disappointed Barrichello had to settle for eighth. The Brazilian will now go into the season finale in Abu Dhabi trailing Vettel by two points in the race for the runner-up slot.
Kovalainen finished ninth ahead of Kobayashi, who was impressive on his debut with Toyota but could also find himself in trouble with the stewards after an incident which saw him cut across on countryman Nakajima as the Williams man came out from the pits after his first stop. Nakajima lost the nose of his car in the incident and went off heavily into the barriers at turn four to cap a miserable race for his team after Rosberg was forced out with mechanical woes.
Aside from the three first lap casualties, Nick Heidfeld was the only other retirement as he suffered a failure of his fuel rig on his first stop and then ran out of fuel on returning to the track.
Not only has Button now clinched the drivers' title, but Brawn GP are the constructors' champions less then eleven months after it appeared that the Brackley-based team could be forced to close its doors when Honda announced it was to quit the sport.
To view the results of the race, CLICK HERE