Jenson Button posted the fastest time for McLaren as Formula One got back to business on Friday with the first practice session for the season-opening Australian Grand Prix.
The former world champion, one of an unprecedented six in the field this year, edged team mate and compatriot Lewis Hamilton into second place by 0.245 seconds on the timesheets with a quickest lap of one minute 27.560 seconds.
Seven-times champion Michael Schumacher had put Mercedes on top with the quickest of his 17 laps (1.28.235) for much of the session confirming his Mercedes team's promising pre-season testing before being bettered by the McLaren duo.
Fernando Alonso (1.28.360) was fourth fastest for Ferrari despite a dangerous wobble coming into the home straight on the last of his 21 laps.
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 world champion team mate Sebastian Vettel down in 11th.
With teams using a variety of set-ups and fuel loads in the early practice sessions, however, not a great deal will be read into the relative speed of the cars.
Former champion Kimi Raikkonen, returning this season with Lotus after two years out of the sport, ran just eight laps and recorded the ninth quickest time in 1.29.565.
Brazilian Felipe Massa, fighting for his drive at Ferrari after a miserable 2011, had a morning to forget after sliding into the gravel midway through the session and managing just the 18th quickest time.
Toro Rosso's French rookie Jean-Eric Vergne was first out on a track still wet from the morning rain and all but the HRT of Pedro de la Rosa got out of the garage during the 90 minute session.
A second practice session follows later on Friday. -Reuters
AUSTRALIAN GP FIRST PRACTICE - TOP TEN
1. Jenson Button (McLaren) - 1:27.560
2. Lewis Hamilton (McLaren) - 1:27.805
3. Michael Schumacher (Mercedes) - 1:28.235
4. Fernando Alonso (Ferrari) - 1:28.360
5. Mark Webber (RedBull) - 1:28.467
6. Nico Rosberg (Mercedes) - 1:28.683
7. Daniel Ricciardo (Ferrari) - 1:28.908
8. Pastor Maldonado (Williams-Renault) - 1:29.415
9. Kimi Raikkonen (Lotus-Renault) - 1:29.565
10. Kamui Kobayashi (Sauber-Ferrari) - 1:29.722