The McLarens of Britons Jenson Button and Lewis Hamilton posted the fastest times as Formula One roared back to business with the first two practice sessions for the season-opening Australian Grand Prix today.
Button edged fellow former world champion Lewis Hamilton into second place by 0.245 seconds on the timesheets with a quickest lap of one minute 27.560 seconds in the first session.
A torrential downpour between the two sessions meant the times in second practice were down on the first, with most teams running wet weather tyres for all but the last 15 minutes.
"Even though it doesn't mean too much, it's always nice to start the season with the quickest time of the day," Button, who won at Albert Park in 2009 and 2010.
"The weather didn't help, but it's been the same for everyone. Overall, I think we're quite happy."
Seven-times champion Michael Schumacher had put Mercedes on top for much of the opening session with the quickest of his 17 laps (1.28.235) to confirm his Mercedes team's promising pre-season testing.
The 43-year-old German, who has yet to get on the podium since his return to the sport two years ago, also registered the fastest time in the second session in 1.29.183 ahead of Force India's Nico Hulkenburg.
Red Bull's Mark Webber, who will be looking to better his best finish of fifth in his 11th home grand prix, was fifth fastest with his reigning world champion team mate Sebastian Vettel 11th in the first session and 10th in the second.
The 24-year-old German, seeking a third successive world title this year, was not unduly concerned.
With teams using a variety of set-ups and fuel loads in the early practice sessions, little will be read into the relative speed of the leading contenders.
"I think obviously with the conditions it's difficult to get a lot of running but it was the same for all of us," Vettel, who won from pole here last year, said. "The important thing is to make a step overnight and go from there."
Fernando Alonso, another of the unprecedented six former world champions in the field, was fourth fastest for Ferrari in 1.28.360 despite a dangerous wobble coming into the home straight on the last of his 21 laps in the morning.
Former champion Kimi Raikkonen, returning this season with Lotus after two years out of F1, ran just 15 laps over both sessions and recorded the ninth quickest time in the morning of 1.29.565.
Toro Rosso's French rookie Jean-Eric Vergne was first out on a track still wet from the morning rain and only the HRT of Pedro de la Rosa failed to get out of the garage during the opening 90-minute session.
The Spaniard did get his car onto the track in the second session but failed to complete a lap and HRT boss Luis Perez-Sala said it would be "difficult" for the team to qualify for the race.
A third practice session takes place on Saturday before qualifying for Sunday's race.
"It still looks close between ourselves, Red Bull and Mercedes," said Hamilton.
"It's going to be interesting tomorrow - we'll get a better understanding of who's going to be quick. I'm massively excited to see how the rest of the weekend goes."