LONDON, England (CNN) -- Brawn GP's Jenson Button has won the 2009 Formula One drivers championship after finishing fifth in the Brazilian Grand Prix at Interlagos.
Champion at last. Jenson Button celebrates winning the drivers' championship in Brazil.
The 29-year-old Briton finished ahead of both his championship rivals Rubens Barrichello and Sebastian Vettel, giving him an unassailable lead in the championship with just one race remaining.
Red Bull's Mark Webber won the race with BMW's Robert Kubica finishing second.
Button's compatriot and out-going world champion Lewis Hamilton came home third.
Starting from a grid position of 14th, Button made steady progress up the field after a series of impressive overtaking maneuvers.
The result also means that Button's Brawn GP team have claimed the constructors' title.
After the race, Button told the BBC: "It's amazing. After the last few races I've had, this makes up for it. It was such an awesome race.
"21 years ago I jumped into a car and I loved winning. I never expected to be world champion in Formula One but I've done it today."
Drivers' Championship (after 16 rounds)
1: Jenson Button GB Brawn-Mercedes 89 (C)
2: Sebastian Vettel Ger Red Bull-Renault 74
3: Rubens Barrichello Brz Brawn-Mercedes 72
4: Mark Webber Aus Red Bull-Renault 61.5
5: Lewis Hamilton GB McLaren-Mercedes 49
6: Kimi Raikkonen Fin Ferrari 48
7: Nico Rosberg Ger Williams-Toyota 34.5
8: Jarno Trulli Ita Toyota 30.5
9: Fernando Alonso Spa Renault 26
10. Timo Glock Ger Toyota 24
11: Felipe Massa Brz Ferrari 22
12: Heikki Kovalainen Fin McLaren-Mercedes 22
13: Robert Kubica Pol BMW Sauber 17
14: Nick Heidfeld Ger BMW Sauber 15
15: Giancarlo Fisichella Ita Ferrari 8
16: Adrian Sutil Ger Force India-Mercedes 5
17: Sebastien Buemi Swi Toro Rosso-Ferrari 5
18: Sebastien Bourdais Fra Toro Rosso-Ferrari 2
19: Kazuki Nakajima Jpn Williams-Toyota 0
20: Nelson Piquet Jr Brz Renault 0
21: Jaime Alguersuari Spa Toro Rosso-Ferrari 0
22: Romain Grosjean Fra Renault 0
23: Luca Badoer Ita Ferrari 0
24: Vitantonio Liuzzi Ita Force India 0
1: Brawn-Mercedes 161 (C)
2: Red Bull-Renault 135.5
3: McLaren-Mercedes 71
4: Ferrari 70
5: Toyota 54.5
6: Williams-Toyota 34.5
7: BMW Sauber 32
8: Renault 26
9: Force India-Mercedes 13
10: Toro Rosso-Ferrari 7