None of the Ferraris and McLarens were even in the top ten, having all hit traffic or had to slow for incidents on their soft-tyre laps.

The session was a flurry of activity throughout, with a wide variety of drivers and teams - from the Ferrari drivers to Toro Rosso's Sebastian Vettel - appearing at the top of the timing screens over the course of the hour.

Fernando Alonso ultimately ended up third for Renault, while champions Ferrari managed only 11th and 14th places, with Felipe Massa and Kimi Raikkonen respectively.

The McLarens were back in 12th and 20th - Lewis Hamilton lapping 0.9 seconds quicker than teammate Heikki Kovalainen.

The action started early, with Timo Glock recovering from a trip across the Turn 15 grass to hit the top of the timesheets for Toyota briefly before the top contenders emerged after 20 minutes.

Felipe Massa immediately usurped Glock with a 1:27.707 lap, but the Ferrari driver's time in front was short-lived, as first position then changed hands five times in just two minutes.

First Fernando Alonso beat Massa's time by 0.3 seconds, then the Renault driver was pushed back by first Raikkonen's Ferrari (which lapped 0.043 seconds faster) and then Williams' Nico Rosberg, who raised the benchmark to a 1:27.196.

But just seconds after the German had done so, Alonso improved again on his next lap and retook the top spot by 0.029 seconds.

McLaren did not join the battle at the front when they emerged. Hamilton slid across the grass at Turn 1 on his first flying lap, before taking fourth place next time around, while Kovalainen's opening run left him only 13th - albeit just 0.8 seconds off the pace.

Raikkonen usurped Alonso with 20 minutes remaining - sneaking ahead of the Renault by a scant 0.004 seconds. The world champion then became the latest driver to explore the grass at Turn 1, but continued without drama.

The pace then increased dramatically as teams went into fully-fledged qualifying mode, leading to a number of unusual names appearing near the front.

Toro Rosso's Sebastian Vettel sprang the first surprise with 12 minutes to go, as he beat Raikkonen's time by half a second to go fastest of all. Moments later Force India's Giancarlo Fisichella came within 0.035 seconds of beating him and took second place using the softer tyres, while Friday practice star Mark Webber put his Red Bull into third.

After five minutes in front, Vettel's time was beaten by Rosberg, who improved to a 1:26.171 - nearly half a second clear of the field - on the soft compound Bridgestones.

Alonso then tried the same tyres for the first time and retook first place, pipping Rosberg by 0.089 seconds with three minutes remaining, but his time was soon beaten by the BMW duo, as first Nick Heidfeld set a 1:25.950, then his teammate Kubica beat him by 0.337 seconds to end this unpredictable session on top.

Rosberg and Red Bull's David Coulthard completed the top five behind Alonso, with Webber sixth ahead of Honda's Jenson Button, Vettel, Fisichella and Jarno Trulli's Toyota.

While Alonso took a big step closer to the front-runners in this session, his Renault teammate Nelson Piquet continued to struggle. The Brazilian rookie went through the Turn 3 gravel trap after nearly spinning on the entry to the corner, and ended the hour in 15th position.