Casey Stoner was quickest again in final practice at Catalunya, completing his clean sweep of all three sessions so far this weekend.
The Honda rider's 1m42.691s on only his fourth lap of the morning was good enough to keep him in front until the end.
But Yamaha showed better form than on Friday, with Jorge Lorenzo taking second and closing to within 0.122 seconds of Stoner on his last run.
Marco Simoncelli remained among the front group in third on the Gresini Honda, ahead of the second Yamaha of Ben Spies and Stoner's teammate Andrea Dovizioso.
Nicky Hayden was an encouraging sixth for Ducati, while his teammate Valentino Rossi was eighth after crashing at Turn 5. The Italian lost control on the way into the corner but was able to quickly walk away unhurt and was back out on his spare bike within five minutes.
Loris Capirossi had an accident at the same spot, and was also unhurt, rejoining on his spare bike to take ninth in the end. His Pramac Ducati team-mate Randy de Puniet took a trip through the gravel without incident and later stalled on track while trying to do a practice start after the chequered flag.
Tech 3 Yamaha's sole representative for the rest of the weekend Cal Crutchlow split the Ducatis in seventh, and Alvaro Bautista completed the top 10 on the Suzuki.
Pos Rider Team/Bike Time Gap
1. Casey Stoner Honda 1m42.691s
2. Jorge Lorenzo Yamaha 1m42.813s + 0.122s
3. Marco Simoncelli Gresini Honda 1m43.130s + 0.439s
4. Ben Spies Yamaha 1m43.478s + 0.787s
5. Andrea Dovizioso Honda 1m43.628s + 0.937s
6. Nicky Hayden Ducati 1m43.669s + 0.978s
7. Cal Crutchlow Tech 3 Yamaha 1m43.883s + 1.192s
8. Valentino Rossi Ducati 1m44.364s + 1.673s
9. Loris Capirossi Pramac Ducati 1m44.457s + 1.766s
10. Alvaro Bautista Suzuki 1m44.504s + 1.813s
11. Karel Abraham Cardion Ducati 1m44.510s + 1.819s
12. Randy de Puniet Pramac Ducati 1m44.541s + 1.850s
13. Hiroshi Aoyama Gresini Honda 1m44.642s + 1.951s
14. Hector Barbera Aspar Ducati 1m44.762s + 2.071s
15. Toni Elias LCR Honda 1m44.963s + 2.272s