The Italian was slower than the Williams driver in both of the first two sectors, but blitzed the final element of the lap to sneak ahead of Schumacher with a time of 1m22.358s.

"It's a good boost ahead of tomorrow," said Trulli. "We have to improve a little bit, but we'll see. It's difficult to say how second qualifying will pan out."

Ferrari's Michael Schumacher and Juan Pablo Montoya of Williams-BMW, the two major championship protagonists, had a tough time running first and second on the dusty Hungaroring circuit. Schumacher made a mistake that cost him time in the final sector on his way to ninth, with Montoya one spot ahead of him.

"I maybe braked a bit too early for Turn 1," said Montoya. "The track conditions were very difficult."

Mark Webber was third quickest for Jaguar, and was actually quickest at the second split but lost time in the final sector. He benefited from running 10th on the road, as the dusty track conditions made things tricky for the early runners.

McLaren's David Coulthard, another driver to have his contract renewed for next season, put in one of his most impressive showings in a Friday qualifying session to take fourth, ahead of Rubens Barrichello (Ferrari) and Fernando Alonso (Renault).

"It wasn't a bad lap, although I had a bit too much oversteer," said Barrichello, while Alonso bemoaned an engine problem which curtailed his running in the earlier free practice session: "The track suits our car well, so we can be quick here. Pole tomorrow will be difficult for us, but not impossible."

Olivier Panis did not live up to pre-session expectations and was only seventh quickest. He could not reproduce the fantastic lap he managed in free practice this morning, while team-mate Cristiano da Matta spun at the penultimate corner to cloud Toyota's otherwise promising day.

Nick Heidfeld scraped into the top 10 despite running very wide at Turn 3, while Sauber team-mate Heinz-Harald Frentzen was almost as quick as Trulli and R Schumacher through the opening sector, but lost 1.3secs over the rest of the lap and ended the session 11th.

McLaren's Kimi Raikkonen looked good in the opening two-thirds of his lap, but a poor final sector – coupled with the improving track conditions for the later runners – dumped him back to 12th. BAR-Honda duo Jenson Button, who held an impressive slide at the first corner, and Jacques Villeneuve were next up.

Justin Wilson was 15th quickest for Jaguar, but provided the scare of the day when he tankslapped through the ultra-quick Turn 3. He was still easily quicker than the Jordans of Giancarlo Fisichella and Ralph Firman, plus the Minardis of Jos Verstappen and Nicolas Kiesa.