AUSTRALIAN GRAND PRIX
Albert Park, Melbourne
Comprehensive live coverage of Friday's practice sessions, Saturday's qualifying sessions and Sunday's race across BBC TV, radio and online.
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Replay - Australian GP second practice
Williams driver Nico Rosberg clocked the fastest laps of both practice sessions as the new Formula 1 season burst into life in Melbourne.
Toyota, Brawn GP and Williams - who all fought off a Thursday protest about the legality of their cars - shone the brightest on an intriguing afternoon.
Britain's Lewis Hamilton, the world champion, struggled in his McLaren to finish 16th then 18th.
Red Bull put in a strong second session while Ferrari had a mixed day.
Ahead of the richly-anticipated opening action of the 2009 season, motorsport's governing body, the FIA, had rejected a protest made by Ferrari, Red Bull and Renault about the legality of a key part at the back of the cars used by Williams, Brawn GP and Toyota.
Kubica concerned by poor grip
It had been claimed their rear diffusers do not conform to new F1 regulations, but stewards ruled against the complaint.
And it was those cars that were fastest around Melbourne's Albert Park street circuit, with the traditionally more successful teams suffering.
In the first session, Rosberg came through to take the fastest time - one minute 26.687 seconds - from Ferrari's Kimi Raikkonen on his last lap of 19, while team-mate Kazuki Nakajima finished second.
The German ran even quicker in the second session, clocking 1:26.053, while Japan's Nakajima finished up seventh.
"It's been a positive day," said Rosberg. "We've done very well today but it's not clear how much fuel others were running.
"My hopes are higher than before that we can consistently score points. It's a nice step forward but how much, I cannot say."
New team Brawn GP also backed up their impressive performance in testing with a strong showing.
The former Honda team led by owner Ross Brawn were tipped as pre-race favourites and, on this early showing, there is every indication that may be justified.
Veteran Rubens Barrichello, at 37 the oldest driver on the grid, finished fourth and second in the respective sessions with a fastest time of 1:26.157.
Massa struggles with tyres during practice
England's Jenson Button - widely identified as the pre-race favourite by bookies - finished sixth and fifth with a fastest time of 1:26.374.
Though little can be read into practice times - teams merely use these sessions to determine their qualifying and race tactics - Toyota will also be heartened by their performance.
Drivers Jarno Trulli and Timo Glock, both running on the softer of the two tyre types available, led for much of the second session and eventually finished third and sixth respectively.
Also on the seemingly more responsive softer tyres, Raikkonen led for most of the first session but eventually finished third for the constructor's champions.
In the second session, he finished 11th with Ferrari team-mate Felipe Massa one place ahead.
McLaren were slow throughout, which was largely expected given the problems they had experienced in pre-season testing.
Heikki Kovalainen finished fifth in the first session but team-mate Hamilton was well off the pace and both were in the last four places in the second session.
"It's tough for anyone [being at the back] but I have a lot of experience running at the back in other categories," said Hamilton.
"But we are not in the place we want to be. We have a steep and tough challenge but we have to remain positive and keep pushing."
Two-time world champion Fernando Alonso failed to shine in his Renault, finishing 10th in the first session and 12th in the second, while BMW Sauber had troubles with their car and were not as quick as anticipated after strong test showings leading up to Melbourne.
Red Bull suffered in the first session, with drivers Mark Webber and Sebastian Vettel managing just 11 laps between them.
But Webber hit back to finish fourth in the second session with a time of 1:26.370, though Vettel again span out.
Ferrari, McLaren and Renault, along with BMW Sauber's Nick Heidfeld, ran with the new kinetic energy recovery (Kers), which gives drivers a power boost.
The third and final practice session is on Saturday at 0255 GMT.