Yvan Muller stretched his World Touring Car Championship lead with a narrow victory in the series' maiden American race
The triple WTCC champion was chased home at Sonoma by title rival and RML Chevrolet team-mate Rob Huff, who was just half a second adrift at the chequered flag.
Muller's eighth victory of the season was achieved after power-steering gremlins dropped the third factory Chevrolet of Alain Menu from contention.
Polesitter Menu survived a wheel-banging session with fast-starting front-row man Gabriele Tarquini at Turn 2 on the opening lap.
Lukoil SEAT racer Tarquini was squeezed off the road and dropped to fifth, while Menu held his ground to maintain the lead ahead of Muller, Huff and Yokohama Drivers' Trophy leader Norbert Michelisz.
Further back, Stefano D'Aste gave the occupiers of a marshal post a scare when he spun off on the inside at Turn 2. Darryl O'Young, Alberto Cerqui and Pepe Oriola were involved in a separate melee on the outside of the corner.
The three blue Cruzes ran in close formation until Menu slowed entering the Carousel on lap four, allowing both Muller and Huff to dive through.
Menu pitted at the conclusion of the lap, having survived a trip through the scrub lining the Sonoma circuit.
Promoted into third place, Michelisz was unable to threaten the lead pair. But the Hungarian appeared to exert little effort in extending a comfortable 3.4s margin over Tarquini at the finish.
Bamboo Engineering's Alex MacDowall recorded his highest finish of the season in fifth, ahead of Tiago Monteiro's Tuenti SEAT.
After a troubled qualifying session, Tom Coronel made startling progress from 21st on the grid to take eighth for ROAL Motorsport.
In an eventful race, Coronel inadvertently sent fellow BMW runner Mehdi Bennani into a spin at the Carousel on lap eight. The Moroccan recovered to finish 11th, behind Tom Boardman, up from 20th, and reversed-grid polesitter Stefano D'Aste.
Results - 13 laps:Pos Driver Team/Car Time/Gap 1. Yvan Muller Chevrolet 23m34.369s 2. Rob Huff Chevrolet + 0.564s 3. Norbert Michelisz Zengo BMW + 5.444s 4. Gabriele Tarquini Lukoil SEAT + 8.847s 5. Alex MacDowall Bamboo Chevrolet + 11.803s 6. Tiago Monteiro Tuenti SEAT + 12.422s 7. Franz Engstler Engstler BMW + 15.707s 8. Tom Coronel ROAL BMW + 16.341s 9. Stefano D'Aste Wiechers BMW + 17.304s 10. Tom Boardman Special Tuning SEAT + 25.823s 11. Mehdi Bennani Proteam BMW + 30.314s 12. Tom Chilton Arena Ford + 34.388s 13. Robb Holland Bamboo Chevrolet + 40.092s 14. Darryl O'Young Special Tuning SEAT + 46.184s 15. Charles Ng Engstler BMW + 47.864s Retirements: Pepe Oriola Tuenti SEAT 10 laps James Nash Arena Ford 9 laps Alain Menu Chevrolet 9 laps Fernando Monje SUNRED SEAT 8 laps Alberto Cerqui ROAL BMW 1 lap Aleksei Dudukalo Lukoil SEAT 0 laps
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