McLaren's Juan Pablo Montoya won the Italian Grand Prix on Sunday while Renault's Fernando Alonso took a giant step towards becoming Formula One's youngest champion.
Ferrari's seven times world champion Michael Schumacher failed to score a point for the second race in a row and was mathematically ruled out of title contention for the first time since 1999, ending Formula One's longest reign.
The German, a sad 10th in front of a far smaller crowd than usual at Ferrari's home circuit, has been champion since 2000.
India's Narain Karthikeyan finished behind the pack in 20th position.
Alonso, 24, finished a close runner-up to stretch his championship lead over Colombian Montoya's unlucky team mate Kimi Raikkonen, now his sole rival and fourth on Sunday, to 27 points with four races remaining.
Renault's Italian Giancarlo Fisichella took third place and his team remained eight points clear of McLaren in the constructors' standings.
Raikkonen could again only curse his misfortune.
After winning the last two races, the Finn knew he had a mountain to climb when an engine failure on Saturday cost him pole position and 10 places on the starting grid.
Starting 11th, he clawed his way up to second place behind Montoya before pitting and dropping back to fifth.
With enough fuel on board not to have to make another stop, he was sitting comfortably until having to pit again three laps later for a new rear left tyre.
The Finn rejoined in 12th place, his efforts wasted.
Raikkonen still provided the fascination of a race low on incident by reeling off fastest laps and roaring back to fourth place before a spin allowed Toyota's Italian Jarno Trulli back in front.
Trulli's advantage was short-lived, however, Raikkonen passing him to at least limit the damage.
The Italian finished fifth, ahead of German team mate Ralf Schumacher, while Brazilian stand-in Antonio Pizzonia was an impressive seventh for Williams after replacing unwell German Nick Heidfeld.
Briton Jenson Button claimed the final point for BAR.
1. Juan Pablo Montoya (Colombia) McLaren 1:14:28.659
2. Fernando Alonso (Spain) Renault +00:02.479
3. Giancarlo Fisichella (Italy) Renault 00:17.975
4. Kimi Raikkonen (Finland) McLaren 00:22.775
5. Jarno Trulli (Italy) Toyota 00:33.786
6. Ralf Schumacher (Germany) Toyota 00:43.925
7. Antonio Pizzonia (Brazil) Williams 00:44.643
8. Jenson Button (Britain) BAR 01:03.635
9. Felipe Massa (Brazil) Sauber 01:15.413
10. Michael Schumacher (Germany) Ferrari 01:36.070
11. Jacques Villeneuve (Canada) Sauber 1 lap
12. Rubens Barrichello (Brazil) Ferrari 1 lap
13. Christian Klien (Austria) Red Bull 1 lap
14. Mark Webber (Australia) Williams 1 lap
15. David Coulthard (Britain) Red Bull 1 lap
16. Takuma Sato (Japan) BAR 1 lap
17. Tiago Monteiro (Portugal) Jordan 2 laps
18. Robert Doornbos (Netherlands) Minardi 2 laps
19. Christijan Albers (Netherlands) Minardi 2 laps
20. Narain Karthikeyan (India) Jordan 3 laps.
(rank: r = retired, nc = not classified)