Felipe Massa gained a crucial advantage over world title rival Lewis Hamilton as he took pole position for Sunday's title-deciding Brazilian Grand Prix.
The Ferrari driver set a benchmark of one minute 12.368 seconds but Hamilton could not match it and finished almost half a second behind in fourth.
Toyota's Jarno Trulli collected second ahead of Ferrari's Kimi Raikkonen.
Hamilton has a seven-point lead in the title race which means Massa must win or finish second to deny him the title.
But even if Massa wins, Hamilton only needs to finish fifth for McLaren to become Britain's first world champion since Damon Hill in 1996 and the youngest ever in the history of the sport.
WHAT HAMILTON NEEDS TO DOHamilton and his McLaren team are determined not to jeopardise his title chances for the second season running in Brazil.
The 23-year-old arrived at Interlagos in 2007 with a seven-point advantage over Raikkonen only to see the title slip through his fingers in a dramatic race.
Hamilton ran wide on his first lap trying to unnecessarily pass then team-mate Fernando Alonso before a freak gearbox problem left him at the back of the field.
Though he recovered to seventh, Raikkonen took the chequered flag and with it the championship by a single point.
With Massa perfectly positioned for victory in Sao Paulo, there is a real danger that the world title could once again elude Hamilton.
"I will try to do my best to win the race, which is the most important thing," said Massa, who claimed his third successive pole in Sao Paulo.
"It's a great start to the weekend. We have 71 laps ahead of us which is pretty long, but it is always better to start at the front.
"It's so nice to make the third pole in Brazil in front of my people; it's difficult to describe but it's a dream come true.
"The pressure is all on his (Hamilton's) shoulders because I have nothing to lose."
The two title rivals recommenced battle in a closely-fought qualifying session at Interlagos.
"I don't need to do anything spectacular - I just need to bring the car home for some good points"
Massa had thrown down the gauntlet in the first session, zooming round his home circuit in a blistering 1:11.830 - the fastest time of the weekend.
Hamilton responded in the second session, bettering the Brazilian to leave the fight for pole finely poised.
But it was Massa who twice set the benchmark in the final qualifying session and Hamilton could not eke out enough pace to eclipse the Brazilian.
A wobble through the Senna S combination - a section of the track he has struggled with all weekend - proved costly and Hamilton will line up on the second row alongside Raikkonen.
"I think finishing in this place, it will be a tough race for sure," said Hamilton.
"We are in a great position to finish the race where we are and to make some steps forward.
"Felipe needed to be on pole and all the best to him but I don't need to do anything spectacular - I just need to bring the car home for some good points."
Trulli recovered from a midweek bout of flu to prevent Ferrari from locking out the front row, claiming a surprise second to hand Toyota their best qualifying result for three years.
"It would be amazing to end the season winning the first victory for Toyota," said the Italian, renowned for his pace over a single lap.
"But we know races, anything can happen and I will be there tomorrow to fight."
606: DEBATEHamilton will have to keep Massa in his sights whilst avoiding getting caught up in traffic if he is to capture a maiden world title in Brazil.
His team-mate Heikki Kovalainen offers some protection in fifth place and with McLaren trailing Ferrari by 11 points in the constructors' title race both drivers need a solid finish.
But Renault's sixth-placed Alonso followed by Sebastian Vettel and BMW Sauber's Nick Heidfeld will all be expected to push hard from the start.
Vettel is competing in his last Grand Prix for Toro Rosso before moving to sister team Red Bull next season as a replacement for David Coulthard.
The Scot squeaked into the second spell of qualifying and will line up in 15th place as he draws the curtain down on a career that has spanned 15 seasons.
"I'd hoped to make it through to the final 10 but it was a bit of a long shot," the 37-year-old told BBC Sport.
"I think it's going to be a challenging race and the best we can hope for is for some incidents up front."
Qualifying result for the Brazilian Grand Prix at Interlagos:
1. Felipe Massa (Brz) Ferrari 1min 12.368secs
2. Jarno Trulli (Ita) Toyota 1:12.737
3. Kimi Raikkonen (Fin Ferrari 1:12.825
4. Lewis Hamilton (GB) McLaren-Mercedes 1:12.830
5. Heikki Kovalainen (Fin) McLaren-Mercedes 1:12.917
6. Fernando Alonso (Spn) Renault 1:12.967
7. Sebastian Vettel (Ger) Toro Rosso-Ferrari 1:13.082
8. Nick Heidfeld (Ger) BMW Sauber 1:13.297
9. Sebastien Bourdais (Fra) Toro Rosso-Ferrari 1:14.105
10. Timo Glock (Ger) Toyota 1:14.230
11. Nelson Piquet (Brz) Renault 1:12.137
12. Mark Webber (Aus) Red Bull-Renault 1:12.289
13. Robert Kubica (Pol) BMW Sauber 1:12.300
14. David Coulthard (GB) Red Bull-Renault 1:12.717
15. Rubens Barrichello (Brz) Honda 1:13.139
16. Kazuki Nakajima (Jpn) Williams-Toyota 1:12.800
17. Jenson Button (GB) Honda 1:12.810
18. Nico Rosberg (Ger) Williams-Toyota 1:13.002
19. Giancarlo Fisichella (Ita) Force India-Ferrari 1:13.426
20. Adrian Sutil (Ger) Force India-Ferrari 1:13.508
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