Toyota's Jarno Trulli beat home favourite Fernando Alonso by a whisker on Saturday to claim provisional pole position for the Spanish Grand Prix.
The Italian lapped the Circuit de Catalunya in one minute 14.795 seconds, just 16 thousandths of a second faster than Renault's championship leader.
Alonso, winner of the last three races, remained well positioned to take pole in Sunday's decisive final session.
"It was something special for me, it's probably my best lap in a Formula One car so far," said Alonso, cheered on by his flag-waving home fans.
India's Narain Karthikeyan finished 15th, ahead of teammate Tiago Monteiro and the two Minardis.
Karthikeyan clocked 1:18.557.
Seven-time champion Michael Schumacher started out very well but lost time in the second intermediate to finish seventh with 1:15.398.
Ralf Schumacher, who set the pace in the final practice, was fourth while his former Williams teammate Juan Pablo Montoya stood at a disappointing 12th. Montoya had suffered a crash in Friday practice.
Only eighteen cars were on track on Saturday as BAR Honda has been banned for the next two races.
Standings after first qualifying:
1. Jarno Trulli (Italy) Toyota 1:14.795
2. Fernando Alonso (Spain) Renault 1:14.811
3. Kimi Raikkonen (Finland) McLaren 1:14.819
4. Ralf Schumacher (Germany) Toyota 1:14.870
5. Nick Heidfeld (Germany) Williams 1:15.038
6. Mark Webber (Australia) Williams 1:15.042
7. Michael Schumacher (Germany) Ferrari 1:15.398
8. Giancarlo Fisichella (Italy) Renault 1:15.601
9. Rubens Barrichello (Brazil) Ferrari 1:15.746
10. David Coulthard (Britain) Red Bull 1:15.795
11. Felipe Massa (Brazil) Sauber 1:15.863
12. Juan Pablo Montoya (Colombia) McLaren 1:15.902
13. Vitantonio Liuzzi (Italy) Red Bull 1:16.288
14. Jacques Villeneuve (Canada) Sauber 1:16.794
15. Narain Karthikeyan (India) Jordan 1:18.557
16. Tiago Monteiro (Portugal) Jordan 1:19.040
17. Christijan Albers (Netherlands) Minardi 1:19.563
18. Patrick Friesacher (Austria) Minardi 1:20.306
