Pepe Oriola led a Chevrolet one-two-three in an interrupted first World Touring Car Championship practice at Sonoma.
The Spaniard was the only man to break into the 1m45s, but was less than one tenth of a second clear of a chasing pack led by the RML Chevrolets of Tom Chilton and Yvan Muller.
Gabriele Tarquini was the first Honda in fourth, 0.346s down, while defending champion Rob Huff - who won here last year with Chevrolet - was a further three tenths of a second down the road in fifth.
The session was halted before the first flying laps were completed when Tom Coronel crashed his BMW at the Turn 11 hairpin.
The Dutchman, who was the fastest BMW in Friday testing, did not get back out.
After a short delay the session resumed and Oriola immediately hit the front and was then never displaced.
The top order was likewise undisturbed, but places changed hands regularly further down the order.
Franz Engstler eventually claimed sixth for his eponymous BMW squad, but not before spinning at Turn 2 at the halfway point - which team-mate Charles Ng then matched minutes later.
Norbert Michelisz also had a moment, running deep and through the gravel at the Turn 9 chicane, but was still able to claim seventh for the Zengo Honda team.
Marc Basseng, Stefano D'Aste and Tom Boardman rounded out the top 10.
Tiago Monteiro, who was fastest in testing yesterday, was only 17th - two spots above the lead Lada of James Thompson.
Pos Driver Team/Car Time Gap Laps
1. Pepe Oriola Tuenti SEAT 1m45.966s 10
2. Tom Chilton RML Chevrolet 1m46.038s +0.072s 12
3. Yvan Muller RML Chevrolet 1m46.047s +0.081s 11
4. Gabriele Tarquini Honda 1m46.312s +0.346s 12
5. Rob Huff Munnich SEAT 1m46.614s +0.648s 11
6. Franz Engstler Engstler BMW 1m46.744s +0.778s 13
7. Norbert Michelisz Zengo Honda 1m46.754s +0.788s 13
8. Marc Basseng Munnich SEAT 1m47.021s +1.055s 13
9. Stefano D'Aste PB BMW 1m47.049s +1.083s 15
10. Tom Boardman Special Tuning SEAT 1m47.132s +1.166s 9
11. Hugo Valente Campos SEAT 1m47.203s +1.237s 12
12. Fernando Monje Campos SEAT 1m47.262s +1.296s 12
13. Alex MacDowall Bamboo Chevrolet 1m47.272s +1.306s 14
14. Mehdi Bennani Proteam BMW 1m47.278s +1.312s 15
15. Darryl O'Young ROAL BMW 1m47.295s +1.329s 16
16. Charles Ng Engstler BMW 1m47.512s +1.546s 15
17. Tiago Monteiro Honda 1m47.541s +1.575s 11
18. James Nash Bamboo Chevrolet 1m47.568s +1.602s 12
19. James Thompson Lada 1m47.584s +1.618s 12
20. Michel Nykjaer Nika Chevrolet 1m47.733s +1.767s 14
21. Fredy Barth Wiechers BMW 1m47.906s +1.940s 15
22. Rene Munnich Munnich SEAT 1m48.089s +2.123s 13
23. Mikhail Kozlovskiy Lada 1m48.400s +2.434s 15
24. Tom Coronel ROAL BMW no time 0