Jorge Lorenzo set a searing pace in Friday afternoon MotoGP practice at Phillip Island, while rivals Dani Pedrosa and Marc Marquez had issues.
Marquez's problem was a crash at Lukey Heights early in the session.
The Honda rider quickly got up unhurt, but could not improve on sixth place when he rejoined the session.
His team-mate Pedrosa had just split an initial Yamaha one-two to take second behind Lorenzo when he had a bizarre mechanical problem in the closing minutes.
An engine mounting bolt had not been properly secured and came loose, forcing Pedrosa to park the bike at the second corner.
Meanwhile Lorenzo had a serene session on his Yamaha, lapping ever faster until a 1m28.961s put him half a second ahead.
Gresini Honda's Alvaro Bautista also crashed but got going again to grab second on his last run.
Pedrosa retained third, ahead of the Yamahas of Valentino Rossi and Cal Crutchlow.
Randy de Puniet was again top CRT rider in a very impressive eighth place, ahead of all the Ducatis and nearly a second faster than Aspar team-mate Aleix Espargaro.
Hector Barbera also had an accident. He was unhurt.
The injured Stefan Bradl was ruled out of the session after assessing his condition in practice one.
Pos Rider Team/Bike Time Gap 1. Jorge Lorenzo Yamaha 1m28.961s 2. Alvaro Bautista Gresini Honda 1m29.438s +0.477s 3. Dani Pedrosa Honda 1m29.478s +0.517s 4. Valentino Rossi Yamaha 1m29.537s +0.576s 5. Cal Crutchlow Tech 3 Yamaha 1m29.667s +0.706s 6. Marc Marquez Honda 1m29.989s +1.028s 7. Bradley Smith Tech 3 Yamaha 1m30.165s +1.204s 8. Randy de Puniet Aspar Aprilia 1m30.215s +1.254s 9. Nicky Hayden Ducati 1m30.609s +1.648s 10. Andrea Dovizioso Ducati 1m30.754s +1.793s 11. Andrea Iannone Pramac Ducati 1m30.792s +1.831s 12. Colin Edwards Forward FTR-Kawasaki 1m30.917s +1.956s 13. Aleix Espargaro Aspar Aprilia 1m31.091s +2.130s 14. Yonny Hernandez Pramac Ducati 1m31.134s +2.173s 15. Hector Barbera Avintia FTR-Kawasaki 1m31.286s +2.325s 16. Hiroshi Aoyama Avintia FTR-Kawasaki 1m31.434s +2.473s 17. Claudio Corti Forward FTR-Kawasaki 1m31.451s +2.490s 18. Danilo Petrucci Ioda-Suter-BMW 1m31.985s +3.024s 19. Michael Laverty PBM Aprilia 1m32.066s +3.105s 20. Luca Scassa Cardion Aprilia 1m32.261s +3.300s 21. Bryan Staring Gresini FTR-Honda 1m32.290s +3.329s 22. Lukas Pesek Ioda-Suter-BMW 1m32.943s +3.982s 23. Damian Cudlin PBM Aprilia 1m34.969s +6.008s