LE MANS, France (Reuters) - Porsche and Force India Formula One driver Nico Hulkenberg looked set to end Audi's long run of success at the Le Mans 24 Hours race after settling into the lead on Sunday.
The number 19 Porsche, shared by Germany's Hulkenberg, Briton Nick Tandy and New Zealand's Earl Bamber, had a margin of more than three minutes over Mark Webber's number 17 Porsche with three hours remaining.
With the first signs of rain reported around the track, the number seven Audi of defending champions Andre Lotterer, Marcel Fassler and Benoit Treluyer was in third place but a lap down on the leaders.
They were still fighting however, with Germany's Lotterer setting a race lap record of three minutes 17.475 seconds.
Audi have won 13 of the last 15 editions of Le Mans while Porsche, who returned with a full factory effort last year, are chasing their 17th win. They last won the race in 1998.
Hulkenberg, who arrived in Le Mans straight from the Canadian Grand Prix and will be heading to Austria after the weekend, is making his debut in the world's oldest sportscar endurance test.
There had been little to separate the two German manufacturers, both part of the Volkswagen stable, going into the night but things started to unwind for Audi after daybreak in western France.
Fassler had to pit shortly before 0700 local after a large part of bodywork flew off the car without warning, costing seven minutes for repairs and pushing the car down to fifth.
The number nine and eight Audis, three laps down after 21 hours, also suffered mechanical problems.
Australian Webber, the former Red Bull Formula One driver who shares his car with New Zealander Brendon Hartley and Germany's Timo Bernhard, had led at the quarter distance.
However, he had to serve a one-minute 'stop and go' penalty after the eight-hours mark after Hartley overtook under yellow warning flags through a slow zone imposed around the Mulsanne corner following the third safety car interlude.
The safety cars came out for a fourth time around the 17 hour mark when Roald Goethe's Aston Martin crashed, with debris across the track.
The safety cars, three of them to cope with the long Le Mans lap, made their first appearance after the first hour when a three car collision dumped oil on the track at the first chicane.
There was a much longer safety car interlude at the end of the third hour, when Frenchman Loic Duval spun and hit the barriers in the number eight Audi at the Indianapolis corner.
Duval nursed the car back to the pits and it resumed the race only four minutes later, with the safety car leading for 45 minutes.
Denmark's retired nine times winner Tom Kristensen had waved the 83rd edition of the race away in bright sunshine on Saturday, watched by a crowd of around 250,000 spectators enjoying a festival atmosphere.
(Reporting by Alan Baldwin, editing by Sudipto Ganguly)