Yvan Muller and Rob Huff shared the race wins and are now joint leaders in the title race following the World Touring Car Championship round at Sonoma in California.
The Chevrolet team-mates sit on top of the standings with 315 points apiece after French driver Muller took the race one win and Britain's Huff matched that result second time out.
Muller and Huff gave the American manufacturer a one-two in race one with Norbert Michelisz taking third for BMW.
The early laps were action-packed with Alain Menu and Gabriele Tarquini colliding and Alain Menu fighting with Muller and Huff for the lead.
As Menu started to drop down the field Michelisz put pressure on the leading duo but could not upset the podium order.
Huff gave Chevrolet a second win of the day in race two and was able to draw level with Muller in the points table.
Muller did not score any points after the stewards imposed a drive through penalty for pushing Franz Engstler into a spin when trying to take the lead from him.
Huff was challenged by Michelisz and Tarquini but was able to hold on for the win.
