Ferrari's Kimi Raikkonen won his first Formula One drivers' championship as Lewis Hamilton's bid came to a dramatic end in the Brazilian Grand Prix.
Raikkonen celebrates his unexpected title victory
Hamilton could finish only seventh, ending his attempt to make history by winning the title in his maiden season.
Problems with his McLaren put Hamilton to the back of the field early on.
His team-mate Fernando Alonso's hopes were dashed as he finished third behind Raikkonen and the Finn's Ferrari team-mate Felipe Massa.
There was a late twist when it emerged race officials were investigating the fuel used by Williams and BMW Sauber, whose cars filled fourth, fifth and sixth places.
But the stewards decided to impose no penalty.
Had they been disqualified, Hamilton would have moved up to fourth, giving him enough points to win the world title.
Finn Raikkonen, who has won two more races than anyone else this season, won the championship with 110 points, with Alonso and Hamilton tied on 109 points.
Hamilton ended the season in second place on countback, with one more second-place race finish than Alonso.
In the race, things started to go wrong for Hamilton from the start. As Massa eased into the lead from pole position, the Englishman was slow away from his second place on the grid, and was passed by Raikkonen before the first corner.
Then, as they entered the first turn, Alonso drew alongside Hamilton on the outside, claiming the inside line and third place as they went into the second part of the chicane.
Hamilton then unwisely and unnecessarily tried to re-pass his team-mate on the outside into the Subida da Lago corner at the end of the back straight.
He got onto the slippery outside of the track, and slid off into the run-off area, rejoining in eighth place.
Raikkonen sensed Hamilton's early mistake might provide him with an opening to snatch victory.
Hamilton slides off the track after an error on the first lap
"I got a good start and was side by side with Felipe," said Raikkonen. "But the main thing was not to race with him, but get past Hamilton.
"I then saw Hamilton go off and I knew maybe we had a chance."
In itself, that error was not enough to end Hamilton's hopes of becoming champion, but worse was soon to come.
Hamilton quickly set about regaining places, but ran into more problems on lap eight, when he slowed almost to a halt as his car slipped out of gear.
The gearbox electronics corrected themselves, enabling Hamilton to get back on his way, but by then had lost more than 40 seconds, and was at the back of the field.
The 22-year-old spent the rest of the afternoon fighting through the field, desperately trying to gain enough places to stop one of his rivals beating him to the world championship.
The Ferraris were in a race of their own in Brazil
In an attempt to ease his task, McLaren chose a radical three-stop strategy, the thinking presumably being that with a lighter car he would find it easier to overtake his rivals.
The teams have to use both of two types of tyre during the race.
And McLaren chose to get the slower, softer tyre out of the way early with a short second stint.
That way, he would be on the faster tyre at the end of the race when nearly all the other drivers were on the slower one.
But the strategy did not pay off.
Hamilton did get up into the points during his third stint but, once Raikkonen assumed the lead after passing Massa during the second pit-stop period, the Englishman needed to finish fifth to stay ahead of the Finn.
And although he drove flat out to the end of the race he simply ran out of time.
Alonso's hold on the title he has held for two years ended in a damp squib.
The Spaniard was never in contention for victory in a race that was dominated by the Ferraris.
And although he had the edge on everyone else, third place was not enough to stay ahead of Raikkonen in the standings.
Brazilian Grand Prix result after 71 laps of Interlagos track:
1. Kimi Raikkonen (Fin) Ferrari one hour 28 minutes 15.270 seconds
2. Felipe Massa (Brz) Ferrari 1.493 secs behind
3. Fernando Alonso (Spa) McLaren-Mercedes +57.019
4. Nico Rosberg (Ger) Williams-Toyota + 1:02.848
5. Robert Kubica (Pol) BMW Sauber +1:10.957
6. Nick Heidfeld (Ger) BMW Sauber +1:11.317
7. Lewis Hamilton (GB) McLaren-Mercedes one lap behind
8. Jarno Trulli (Ita) Toyota one lap
9. David Coulthard (GB) Red Bull-Renault one lap
10. Kazuki Nakajima (Jpn) Williams-Toyota one lap
11. Ralf Schumacher (Ger) Toyota one lap
12. Takuma Sato (Jpn) Super Aguri-Honda two laps
13. Vitantonio Liuzzi (Ita) Toro Rosso-Ferrari two laps
14. Anthony Davidson (GB) Super Aguri-Honda three laps
R Adrian Sutil (Ger) Spyker-Ferrari 43 laps completed
R Rubens Barrichello (Brz) Honda 40 laps
R Heikki Kovalainen (Fin Renault 35 laps
R Sebastian Vettel (Ger) Toro Rosso-Ferrari 34 laps
R Jenson Button (GB) Honda 20 laps
R Mark Webber (Aus) Red Bull-Renault 14 laps
R Sakon Yamamoto (Jpn) Spyker-Ferrari two laps
R Giancarlo Fisichella (Ita) Renault one lap
Key: R = retired