The Colombian moved to the top 54 minutes into the hour-long session with a lap of 1m12.027s, narrowly edging out Toyota test driver Ricardo Zonta.

World championship leader Fernando Alonso broke with his usual policy and decided to get in some mileage in the first session, ending up third fastest on a 1m12.666s.

Nick Heidfeld was fourth quickest for Williams ahead of Jenson Button’s BAR-Honda and McLaren tester (and frequent Friday pacesetter) Pedro de la Rosa.

Takuma Sato in the second BAR, Renault’s Giancarlo Fisichella, Mark Webber (Williams) and Michael Schumacher (Ferrari) rounded out the top 10.

De la Rosa set the ball rolling early in the session with a 1m12.913s, but soon afterwards crawled to a stop with a throttle sensor problem.

Team-mate Kimi Raikkonen’s weekend didn’t get off to an ideal start either.

The Finn was pushing hard on his first flying lap when he overstepped the mark at Turn 11, losing the back end of his McLaren and skating across the gravel.

He returned to the pits without any visible damage but failed to post a time in the session.

Jacques Villeneuve was another to fall foul of Turn 11, likewise rejoining the track after a brief exploration of the scenery.

Narain Karthikeyan, meanwhile, seemed to spend at least as much time off the track as on it in his vigorous attempts to extract some performance from the Jordan around another unfamiliar circuit.