Kimi Raikkonen beat Renault's Formula One leader Fernando Alonso by the blink of an eye to put McLaren on provisional pole position for Sunday's San Marino Grand Prix.
India's Narain Karthikeyan finished 17th on the grid.
The Finnish 'Iceman' lapped Imola's Enzo and Dino Ferrari circuit in one minute 19.886 seconds, just three thousandths quicker than the Spaniard who is chasing his third pole and victory in a row.
Ferrari's seven-times world champion Michael Schumacher, with just two points from three races won by Renault, was third quickest in 1:20.260 with Australian Mark Webber fourth for Williams.
"It would have been good to have a little gap between him and me for tomorrow but we'll see what we can do," said Raikkonen.
The starting grid will be decided on aggregate times after Sunday's final qualifying.
"The car overall is much better than it was in Bahrain," added Raikkonen, who finished third in that last race three weeks ago.
"The conditions seem to suit the car much better than the previous circuit and it was good yesterday straight out of the box. I'm very happy with it."
SCHUMACHER CONFIDENT
Alonso, 10 points clear of Toyota's Italian Jarno Trulli, is in no danger of losing his championship lead in Italy and was also happy with the Renault's performance.
"We did our job. Imola has been historically not a perfect circuit for the Renault but the car is much better this year over the kerbs," he said.
"Okay, we are second, but we are still competitive and we are still fighting for pole and hopefully tomorrow for the victory," he added.
Schumacher's time was perhaps more impressive than the others given that the German had to start much earlier when conditions were less favourable due to his early retirement in Bahrain.
"We have been showing pretty consistently a strong performance over the weekend," he said.
Ferrari, eclipsed in the first three races, have been working flat out to iron out problems with their new car after rushing it into action in Bahrain and Schumacher said they had made big steps.
"The result I think we can see here," he said. "Qualifying sort of confirms what we have been doing so far and we look forward to the race. I think we will be there. It's going to be tight and tough but I think we have an opportunity."
His Ferrari team mate Rubens Barrichello was 11th. Briton Jenson Button, who started on pole at Imola last year and finished second in his best race yet, was fifth fastest for Honda-powered BAR with Trulli sixth.
Austrian Alexander Wurz, the McLaren test driver qualifying for his first race in more than four years as a stand-in for injured Colombian Juan Pablo Montoya, was in eighth place.
Canadian former world champion Jacques Villeneuve was again outpaced by his Sauber team mate Felipe Massa but is sure to start ahead of the Brazilian who had his engine changed on Friday night and will suffer a 10-place penalty.
Italian Vitantonio Liuzzi, making his Formula One debut for Red Bull, was 16th with Alonso's Italian team Giancarlo Fisichella a disappointing 15th after a big wobble at the Rivazza corner on his fast lap.
Qualifying session 1: 1. Kimi Raikkonen (Finland) McLaren 1:19.886 2. Fernando Alonso (Spain) Renault 1:19.889 3. Michael Schumacher (Germany) Ferrari 1:20.260 4. Mark Webber (Australia) Williams 1:20.442 5. Jenson Button (Britain) BAR 1:20.464 6. Jarno Trulli (Italy) Toyota 1:20.492 7. Felipe Massa (Brazil) Sauber 1:20.593 8. Alexander Wurz (Austria) McLaren 1:20.632 9. Nick Heidfeld (Germany) Williams 1:20.807 10. Takuma Sato (Japan) BAR 1:20.851 11. Rubens Barrichello (Brazil) Ferrari 1:20.892 12. Ralf Schumacher (Germany) Toyota 1:20.994 13. Jacques Villeneuve (Canada) Sauber 1:20.999 14. David Coulthard (Britain) Red Bull 1:21.632 15. Giancarlo Fisichella (Italy) Renault 1:21.708 16. Vitantonio Liuzzi (Italy) Red Bull 1:21.804 17. Narain Karthikeyan (India) Jordan 1:23.123 18. Tiago Monteiro (Portugal) Jordan 1:25.100 19. Christijan Albers (Netherlands) Minardi 1:25.921 20. Patrick Friesacher (Austria) Minardi 1:26.484