Romain Dumas and Timo Bernhard have secured Penske Motorsports an eighth successive outright victory in the American Le Mans Series on 'home' turf in the Detroit Sports Car Challenge, at the end of a thrilling battle as the sport made a welcome return to the fabled 'Motor City'.

After Emanuele Pirro had stolen the advantage with just 50 minutes remaining as Audi sought to seal its first overall ALMS success since March, a fraught closing few laps then saw Dumas' Porsche RS Spyder and Pirro's Audi R10 TDI twice exchange the overall lead. The result marked the fourth straight triumph and sixth of the 2007 campaign for LMP2 championship leaders Dumas and Bernhard, while also allowing Porsche to wrap up the LMP2 manufacturers' laurels.

"My car got better and better, had good front grip and it got easier to catch him and pass him," Dumas remarked afterwards. "I saw my car was more stable in the corners, took a different line to Emanuele and overtook him. I looked in my mirror and unfortunately there was a straight after the corner and thought this time it wouldn't be possible, but at the next corner I braked outside and crossed the racing line. It was really fun."

"Roger (Penske) put a really great race track here," added Bernhard, "and it's very nice. We wanted to give him a present like a class or even overall victory. Then we got the front row for the Penske team and he was very happy about that. That's what the fans wanted to see - a Penske win and a close race to the end. It was a good show."

Pirro and team-mate Marco Werner finished first in LMP1 for the third time this season, getting the jump on the sister machine of Dindo Capello and Allan McNish in the pit-stops around the 90-minute mark. The two-three result helped clinch the LMP1 manufacturers' crown in Audi Sport North America's backyard.

"When you start to lead for so long you start to believe a little bit in the impossible," said Pirro, whose challenge was stymied somewhat when slower traffic forced him to go off-line and pick up old tyre rubber in the latter stages of the race. "At the end of the day we finished second after starting eighth and I can only be happy about that. We put on a very good show.

"After the final re-start I started to get a lot of pick-up on my tyres. I saw (Dumas) pushing me more and more. I had to drive around a slow car, but by then I had signed my life sentence and got too much pick-up. I tried to pass him again on the straight but I couldn't manage it."

"Our strategy was really good," concurred Werner. "At the beginning and under the first yellow we added fuel and new tyres and that was the key to going quicker than the LMP2s."

Dyson Racing's Butch Leitzinger and Andy Wallace ultimately wound up fourth overall and second in LMP2, a scant three tenths of a second in front of the Highcroft Racing Acura ARX of Stefan Johansson and David Brabham.

Johnny O'Connell and Jan Magnussen took their third GT1 class success of 2007 and second in a row in their resurgent Corvette Racing Corvette C6R, an early safety car period enabling the duo to move almost a full lap clear of team-mates Oliver Gavin and Olivier Beretta.

"The car ran absolutely perfectly," enthused Magnussen, who had similarly qualified on the class pole. "I was able to build up about a ten-second gap to when the safety car came out. It was a good place for us and took some pressure away. Things like that can happen here because of the street circuit."

"If there is any one group of guys that I'm proud of, it's the mechanics on the #3 car," O'Connell added. "Through our drought, they never gave up. To finally get to show GM executives what the baddest hotrod GM builds and see what they only hear about from Le Mans is a magical moment."

In GT2, meanwhile, Risi Competizione team-mates Jaime Melo and Mika Salo took to the top step of the podium for the seventh time this year and third in a row, seeing off a stern challenge from Porsche factory pilot Patrick Long following the final re-start to ultimately come home just over 20 seconds ahead of the Flying Lizard Porsche 911 GT3 RSR. Peter Dumbreck and Dirk Muller finished third in class in Petersen Motorsports/White Lightning Racing's Ferrari.

"At the end it was quite difficult," said Melo. "After the safety car I had a lot of pick up on the tyres and the car was sliding around everywhere. After about two laps the Porsche was really close and it took four laps to get the grip, but after that the car was great."

What's more, in victory Melo and Salo strengthened their GT2 title lead over the Flying Lizard pairing of Johannes van Overbeek and J?rg Bergmeister, who saw their Porsche go up in flames when an oil line broke as a result of contact with another GT2 competitor. The duo failed to complete the required 70 per cent of the race in order to record championship points.

"It was a shame what happened to them," commented Salo, "but we've had some bad luck at points this year too. I hope they can be prepared for the next race. There is a little less pressure now certainly, but we will still be going for wins."