2007 world champion Casey Stoner topped the opening practice session at a chilly Phillip Island on his Ducati in a session affected by rain.
Ducati rider Stoner topped the times just after the 20 minute mark, and lowered the mark four more times on his next four laps to a best of 1:31.132, over a second faster than his nearest rival as rain hit the circuit shortly after Stoner set his ultimate mark.
Riders took to the circuit again in the closing minutes but couldn't get close to their earlier bests, which themselves may not have been entirely representative for every rider.
Kawasaki's Randy de Puniet was second fastest in the session with a 1:32.471, 1.339 seconds slower than Stoner with Valentino Rossi on his Yamaha third fastest, 2.3 seconds slower than Stoner.
John Hopkins led a group of five riders split by three-tenths of a second, the group also including Dani Pedrosa, Motegi winner Loris Capirossi, local rider Anthony West and Carlos Checa, the group about three seconds slower than Stoner. After a poor weekend in Japan, tenth fastest for Suzuki's Chris Vermeulen looks promising.
Behind Vermeulen at the end of the session were two of the early pace-setters on a damp but drying track early in the session, Sylvain Guintoli and Marco Melandri. Both riders topped the times during the first 20 minutes of the session but ended the session in 12th and 14th respectively.
Chas Davies, who will ride the final three rounds for Pramac D'Antin Ducati, got off to a good start by setting 15th fastest time and outpacing his teammate Alex Barros by two places and two seconds.
Kurtis Roberts fell during the session but is fine, setting the slowest time.
Pos Rider Make Time 1. Casey Stoner Ducati (B) 1:31.132 2. Randy de Puniet Kawasaki (B) 1:32.471 + 1.339 3. Valentino Rossi Yamaha (M) 1:33.420 + 2.288 4. John Hopkins Suzuki (B) 1:33.862 + 2.730 5. Dani Pedrosa Honda (M) 1:33.890 + 2.758 6. Loris Capirossi Ducati (B) 1:33.975 + 2.843 7. Anthony West Kawasaki (B) 1:34.033 + 2.901 8. Carlos Checa Honda (M) 1:34.167 + 3.035 9. Toni Elias Honda (B) 1:34.397 + 3.265 10. Chris Vermeulen Suzuki (B) 1:34.728 + 3.596 11. Colin Edwards Yamaha (M) 1:35.244 + 4.112 12. Sylvain Guintoli Yamaha (D) 1:35.598 + 4.466 13. Nicky Hayden Honda (M) 1:35.791 + 4.659 14. Marco Melandri Honda (B) 1:35.981 + 4.849 15. Chaz Davies Ducati (B) 1:36.118 + 4.986 16. Makoto Tamada Yamaha (D) 1:37.764 + 6.632 17. Alex Barros Ducati (B) 1:38.145 + 7.013 18. Shinya Nakano Honda (M) 1:40.908 + 9.776 19. Kurtis Roberts KR212V (M) 1:47.458 +16.326