Andrea Dovizioso was quickest by a massive 1.682 seconds in a wet morning warm-up ahead of today's Czech Grand Prix at Brno.
The session started on a damp but drying track, before more rain arrived in the final moments and put an end to any hope of further improvements.
Dovizioso had got an excellent lap in at the right moment to lead the way on 2m10.135s, with his Honda team-mate Dani Pedrosa next up.
Ducati's Casey Stoner equalled Pedrosa time to take third, ahead of championship leader Jorge Lorenzo, whose Yamaha team-mate Valentino Rossi only completed a few tentative laps and ended up 16th.
The conditions unsurprisingly saw unusual names near the front, with the underdogs led by Gresini Honda's Marco Melandri in fifth and Pramac Ducati's Mika Kallio in sixth.
After his practice crash yesterday, Suzuki's Alvaro Bautista was cleared to return to the track, though he was slowest of all as he nursed his battered back.
Pos Rider Team Time Gap
1. Andrea Dovizioso Honda 2m10.135s
2. Dani Pedrosa Honda 2m11.817s + 1.682s
3. Casey Stoner Ducati 2m11.817s + 1.682s
4. Jorge Lorenzo Yamaha 2m11.869s + 1.734s
5. Marco Melandri Gresini Honda 2m12.129s + 1.994s
6. Mika Kallio Pramac Ducati 2m12.138s + 2.003s
7. Nicky Hayden Ducati 2m12.156s + 2.021s
8. Alex de Angelis Interwetten Honda 2m12.829s + 2.694s
9. Colin Edwards Tech 3 Yamaha 2m13.053s + 2.918s
10. Loris Capirossi Suzuki 2m13.284s + 3.149s
11. Randy de Puniet LCR Honda 2m13.450s + 3.315s
12. Aleix Espargaro Pramac Ducati 2m13.650s + 3.515s
13. Hector Barbera Aspar Ducati 2m13.686s + 3.551s
14. Marco Simoncelli Gresini Honda 2m13.765s + 3.630s
15. Ben Spies Tech 3 Yamaha 2m13.917s + 3.782s
16. Valentino Rossi Yamaha 2m16.185s + 6.050s
17. Alvaro Bautista Suzuki 2m17.877s + 7.742s