Emanuele Pirro and Frank Biela claimed one of the tightest victories in American Le Mans Series history when they squeezed over the line in the Generac 500 at Road America just 0.4secs up on their Audi Sport team-mates and a further three tenths up on the Dyson Lola.

Far from conceding the 'second a lap' they claimed to be disadvantaged by the latest round of the weight breaks given to their rivals prior to the race, Audi dominated in qualifying and were on course to do so in the race with Allan McNish and Dindo Capello storming into a clear lead over the first 42 laps, a fact helped when Biela went off on the first corner at the start following a tap from James Weaver.

However, a combination of caution periods and slick pit stop work was enough to get Pirro and Biela in front and when the two R10 TDI's were backed up in another caution period with just 15 minutes remaining, the stage was set for a grandstand finish.

Nonetheless, Pirro held on over Road America's various crests and troughs, resisting McNish's attentions to claim victory by the tightest of margins in what is the closest overall win for five years.

James Weaver and Butch Leitzinger did an impressive giant killing impression in their ever improving Dyson Lola to claim a podium slot, although their championship hopes now look all but over with three rounds remaining.

"There are more important things in life than winning a race, but I was really, really, really happy," said Le Mans winner Pirro. "This is something I really love doing. This is probably the best race I've driven. Driving on the limit the whole race is tough to do and I felt I really did that this race."

"The car is as nice as it always been. The R10 is following very close to the R8," Pirro said. "In Le Mans, I wasn't very familiar with the car but now after the three American races I feel like I can really drive the R10 to the limit. I'm getting comfortable with the car so I'm starting to drive the car to the limit. I think Dindo did too, so I'm very pleased. There wasn't one single more drop I could have squeezed."

Following a myriad of reliability problems that in no way reflected their class-leading speed, Penske Porsche finally moved to the top of all four LMP2 championships, with Sascha Maassen's win with new partner Timo Bernhard moving him two points ahead of Intersport's Clint Field and Liz Halliday, the duo having to settle for third.

With Penske Porsche revising their driver line-up to give themselves the best chance of a full-house of titles, Lucas Luhr is still not far off the title having claimed second in class with Romain Dumas. That finish too was a close one, albeit deliberately, with the duo coasting across the line for a perfect PR finish, 0.15secs apart.