Renault's Fernando Alonso is on the verge of retaining his world title after winning the Japanese Grand Prix.
My victory means a lot, not only for me but for the team as well, getting back confidence
The win puts the Spaniard 10 points clear of rival Michael Schumacher, who failed to finish after suffering a rare engine failure in his Ferrari.
The German was leading when his car broke down after his final pit stop.
Alonso will be crowned drivers' champion again if he scores at least a point in the final race at Brazil or Schumacher fails to win at Interlagos.
Schumacher's team-mate Felipe Massa was second at Suzuka, ahead of Renault's Giancarlo Fisichella, the Honda of Jenson Button and McLaren's Kimi Raikkonen.
The Toyotas of Jarno Trulli and Ralf Schumacher were sixth and seventh, with BMW Sauber's Nick Heidfeld taking the final point.
Until Schumacher's retirement, the two championship rivals staged a tense, flat-out battle, matching each other for pace, with Schumacher a handful of seconds ahead for much of the race.
"My victory means a lot, not only for me but for the team as well, getting back confidence," said Alonso.
"At the beginning of the race I thought that we were not in good shape, but we were wrong, actually we were competitive, as good as the Ferrari pace maybe and better than Toyota."
I came out of the pits behind Nick Heidfeld and he was pretty slow so I lost the opportunity to be in front of Fernando
Alonso's pace was a surprise after Ferrari dominated qualifying, but it made for an intriguing Grand Prix.
Massa led away from pole, with Schumacher second, as Alonso moved up one place to fourth by passing Trulli at the first corner.
Schumacher took the lead when Massa let him by at the start of lap three, but the Ferraris did not build the advantage their qualifying pace had suggested they would.
Instead, Alonso, although stuck behind the second Toyota of Ralf Schumacher for the first 13 laps, was still only around six seconds behind his rival when he finally passed Ralf.
The world champion was then nearly a second faster than Schumacher's Ferrari for the lap and a half before his first pit stop on lap 15.
Alonso was able to capitalise on a rare Ferrari mechanical fault
His pace ensured he rejoined ahead of Massa, who had been stuck behind Nick Heidfeld after making an earlier first stop following a puncture.
"I had a puncture so I needed to anticipate the first stop and that was the problem," said Massa afterwards.
"I came out of the pits behind Nick Heidfeld and he was pretty slow so I lost the opportunity to be in front of Fernando."
Now first and second in the race, Schumacher and Alonso were about five seconds apart, and the gap remained stable as they lapped right on the ragged edge throughout the second stint.
It was reminiscent of some of the superb battles Schumacher had staged with double world champion Mika Hakkinen at Suzuka in the past - the world's two greatest drivers driving on the limit at arguably the most demanding circuit.
The gap ebbed and flowed as the two men negotiated lapped traffic, but there was nothing to choose between them until their second stops.
Alonso stopped on lap 35, only a lap before Schumacher, who rejoined with his lead intact.
But as his Ferrari approached the Degner corner about halfway around the lap, plumes of smoke started pouring from the back of the car.
He pulled up, and climbed out looking stern and disbelieving - it was his first engine failure during a race since the 2000 French Grand Prix.
Alonso, who had seen a 25-point lead cut to nothing by Schumacher since June, was left merely to count down the laps to a victory that puts months of frustration behind him.
"I was quite happy with third place - but after Michael's problem the race became quite good for us," added Alonso. "This win is a surprise for us all, a beautiful surprise.
"We have a good situation for the championship, but we will be racing the same way at Interlagos, to win."
Results at the Japanese Grand Prix:
1 Fernando Alonso (Spa) Renault 1hr 23mins 53.413secs
2 Felipe Massa (Brz) Ferrari +00:16.151
3 Giancarlo Fisichella (Ita) Renault 00:23.900
4 Jenson Button (GB) Honda 00:34.101
5 Kimi Raikkonen (Fin) McLaren 00:43.596
6 Jarno Trulli (Ita) Toyota 00:46.717
7 Ralf Schumacher (Ger) Toyota 00:48.869
8 Nick Heidfeld (Ger) BMW Sauber 01:16.095
9 Robert Kubica (Pol) BMW Sauber 01:16.932
10 Nico Rosberg (Ger) Williams-Cosworth at 1 lap
11 Pedro de la Rosa (Spa) McLaren at 1 lap
12 Rubens Barrichello (Brz) Honda at 1 lap
13 Robert Doornbos (Ned) Red Bull-Ferrari at 1 lap
14 Vitantonio Liuzzi (Ita) Scuderia Toro Rosso-Cosworth at 1 lap
15 Takuma Sato (Jpn) Super Aguri-Honda at 1 lap
16 Tiago Monteiro (Por) Midland-Toyota at 2 laps
17 Sakon Yamamoto (Jpn) Super Aguri-Honda at 3 laps
R Scott Speed (USA) Scuderia Toro Rosso-Cosworth 48 laps completed
R Mark Webber (Aus) Williams-Cosworth 39 laps
R Michael Schumacher (Ger) Ferrari 36 laps
R David Coulthard (GB) Red Bull-Ferrari 35 laps
R Christijan Albers (Ned) Midland-Toyota 20 laps
Fastest Lap: Fernando Alonso (Spa) Renault 1min 32.676 on lap 14