Audi returned to its former dominating form at the Mid-Ohio Sports Car Course after taking a 1-2 finish in the Acura Sports Car Challenge with Lucas Luhr and Marco Werner taking the first overall victory for the marque's R10 TDI since April.
The German, who had qualified only fifth fastest, crossed the finish line 7.717secs ahead of the car shared by team-mates Emanuele Pirro and Dindo Capello, despite driving the last hour and 55 minutes with the same set of Michelin tyres and making just one stop for fuel.
Werner started the race, and had already moved up to third on the opening lap, was second by lap three and took the lead for good when he passed polesitter Gil de Ferran's Acura ARX-01b a minute later.
Audi's victory broke a string of consecutive overall wins for Penske Racing, Porsche and LMP2 entries at Mid-Ohio, a year on from Werner and Pirro placing third overall in the first race for the diesel-powered R10 TDI. The drivers credited winter development and a better-handling race car for the improvement in navigating the ups, downs and arounds of the famous road course.
"This is not really a circuit for us and that makes this a sweet one," Werner said, "but, over the off season, we did some good testing with Michelin and made some good steps. We were really good on the street circuits as well. The combination we have is on the top level - a good tyre and a good car."
There also is something to be said for good pit strategy, as the call for fuel only on the last stop saved Luhr and Werner twelve seconds in the pits compared to the other Audi. Given the final winning margin, the decision appears to have won the race.
"The engineers saw the performance of the car under the first safety car, and again how good it was after the second one," Luhr said, "They called over and said we were going to keep them on the car. I wasn't sure at first, but it really was the key for winning and a very good call.
"The first few laps after the safety cars, I pushed like crazy to build a gap. If you go through traffic and have a lead like we did, you are just a little bit more relaxed and that makes the traffic seem not so bad. Things worked out and, even on older tyres, I was able to pull away from the other cars. This was a perfect race and we are very happy."
Penske's Romain Dumas and Timo Bernhard won for the fourth straight year at Mid-Ohio, but had to make do with a third consecutive success there in LMP2 after being beaten to the top step of the overall podium by Audi. Dumas held off a hard-charging David Brabham in the closing minutes - a flashback to last week's race at Lime Rock - and won the class by 0.609secs.