Robert Kubica set the fastest time of the opening free practice session ahead of this weekend's Australian Grand Prix in Melbourne.
The session was half over before anyone started to set flying laps around the Albert Park circuit, after which the McLarens of Lewis Hamilton and Jenson Button, the Mercedes of Nico Rosberg and the Renault of Kubica traded the top spot.
Hamilton was quickest initially until Rosberg broke into the 1m27s. Kubica then hit the top with 15 minutes to go - setting the best time in each of the three sectors - and remained the only driver in the 1m26s.
The Ferraris of Felipe Massa and Fernando Alonso finished the session fourth and sixth quickest, sandwiching the Red Bull of Sebastian Vettel.
Hamilton finished up seventh, not improving his best time in the second half of the session. Sebastien Buemi, Vitaly Petrov and Vitantonio Liuzzi completed the top 10.
Michael Schumacher was 12th fastest, 1.4 seconds slower than team-mate Rosberg, while home hero Mark Webber was 14th, one second slower than Vettel.
Kamui Kobayashi provided most of the session's drama in his Sauber, causing the only two red flag stoppages. Forty minutes into practice, the Japanese clipped the cone on the inside of Turn 11 and ripped half the front wing from his car. The lack of downforce meant he ran wide at Turn 12 - the second half of the fast left-right section on the back straight - and bounced through the gravel.
He was back out 20 minutes later with a new wing fitted, but it came off as he braked for Turn 3 on his outlap. He managed to keep the car out of the wall, but overshot the corner and scattered debris across the circuit.
Kobayashi's team-mate Pedro de la Rosa stopped out on track at the exit of Turn 4 in the final 10 minutes of the session with a clutch failure.
Paul di Resta finished his first Formula 1 practice session in an impressive 11th place for Force India - just one place and four tenths of a second behind Liuzzi. The Briton ran in place of the team's regular racer Adrian Sutil and completed 25 laps in the 90 minutes.
There was no repeat of the Bahrain practice absences for the new teams, with all 24 cars completing installation laps in the first 10 minutes of practice.
Though Jarno Trulli was confined to the pits for most of the first half of the session with a differential problem. Then both Lotus drivers had off-track excursions, with Trulli overshooting the penultimate corner and team-mate Heikki Kovalainen spinning at Turn 9. Petrov was another to spin at Turn 9 after climbing the high kerb and shedding some aero parts from his Renault.
Lotus finished the session as the quickest of the new teams, with Trulli and Kovalainen 19th and 20th - both 4.7 seconds slower than the quickest time. Lucas di Grassi was a second further back for Virgin, with HRT drivers Bruno Senna and Karun Chandhok 6.4 and 7.3 seconds shy of Kubica's benchmark.
Timo Glock was sidelined for most of the session with a gearbox oil leak on his Virgin Racing car. He completed just eight laps and finished at the bottom of the timesheet.
Pos Driver Team Time Laps 1. Kubica Renault 1:26.927 22 2. Rosberg Mercedes 1:27.126 + 0.199 18 3. Button McLaren-Mercedes 1:27.482 + 0.555 22 4. Massa Ferrari 1:27.511 + 0.584 18 5. Vettel Red Bull-Renault 1:27.686 + 0.759 23 6. Alonso Ferrari 1:27.747 + 0.820 21 7. Hamilton McLaren-Mercedes 1:27.793 + 0.866 22 8. Buemi Toro Rosso-Ferrari 1:28.014 + 1.087 21 9. Petrov Renault 1:28.114 + 1.187 25 10. Liuzzi Force India-Mercedes 1:28.192 + 1.265 18 11. di Resta Force India-Mercedes 1:28.537 + 1.610 25 12. Schumacher Mercedes 1:28.550 + 1.623 19 13. Alguersuari Toro Rosso-Ferrari 1:28.572 + 1.645 21 14. Webber Red Bull-Renault 1:28.683 + 1.756 22 15. de la Rosa Sauber-Ferrari 1:29.465 + 2.538 13 16. Barrichello Williams-Cosworth 1:29.712 + 2.785 18 17. Hulkenberg Williams-Cosworth 1:30.249 + 3.322 26 18. Kobayashi Sauber-Ferrari 1:31.588 + 4.661 5 19. Trulli Lotus-Cosworth 1:31.652 + 4.725 13 20. Kovalainen Lotus-Cosworth 1:31.654 + 4.727 26 21. di Grassi Virgin-Cosworth 1:32.831 + 5.904 25 22. Chandhok HRT-Cosworth 1:33.401 + 6.474 24 23. Senna HRT-Cosworth 1:34.251 + 7.324 19 24. Glock Virgin-Cosworth 1:34.924 + 7.998 8 All Timing Unofficial