Toyota lost three cars powered by its Formula One V8 in the opening qualifying session for the Italian Grand Prix, after Nico Rosberg's last-ditch lap failed to escape the drop zone.

The German, being linked to both McLaren and Brawn for 2010, will start from a season-worst 18th, one place behind Williams team-mate Kazuki Nakajima and ahead only of the two Toro Rossos. With Toyota works driver Timo Glock also sinking into the bottom five, it was a poor start to the afternoon for the Japanese giant.

It could have been worse, however, for Jarno Trulli only escaped the axe at the last moment, but was left clinging to qualification for Q2 as Romain Grosjean's improvement pushed him to 15th.

At the head of the times, ownership of P1 changed with some regularity, with Kimi Raikkonen, Rubens Barrichello and Lewis Hamilton all topping the order on a couple of occasions. The Finn eventually ended up on top with a lap of 1min 23.349secs just edging Hamilton into second. The Briton, however, may yet find himself in hot water after suspicions that he impeded STR's Sebastien Buemi late in the session.

Jenson Button also topped the times before ending up third fastest, but life wasn't so comfortable for his Red Bull rivals, with Sebastian Vettel and Mark Webber only claiming sixth and eleventh in the closing minutes. Free practice pacesetter Adrian Sutil was seventh, one place ahead of new team-mate Tonio Liuzzi, while Giancarlo Fisichella scraped into Q2 in twelfth place.