The 2011 Le Mans 24 Hour is set for an enthralling finish, with the lead Audi and Peugeot entries separated by just 13s at three-quarter distance.
The #2 Audi swapped the lead with the #9 and #7 Peugeots during the morning's pitstop cycles – the three cars taking advantage of the cool conditions to run at near qualifying pace.
Bernoit Treluyer is once again at the wheel of the sole remaining Audi as the race enters its final six hours, with Simon Pagenaud at the wheel of the #9 Peugeot.
Alex Wurz sits less than 30s behind Treluyer in car #7, while Peugeot's #8 entry remains fourth, but lost further time towards the end of Hour 18 thanks to a 60s stop-go penalty for a pitstop infringement.
The four leading cars ran in close company during Hour 18, with the Audi continuing to run faster but less frugally than its French rivals.
The #16 Pescarolo Sport entry remains as the best of the petrol engined cars in sixth place, nine laps behind Treluyer, while the #10 Team Oreca Matmut Peugoet, #12 Rebellion Racing Lola-Judd and #22 Kronos Racing Lola Aston Martin round out the top eight.
Ninth outright is the LMP2 leading #41 Graeves Motorsport Zytek Nissan, which sits four laps clear of the Signatec Oreca Nissan.
The Safety Car was called upon three in the third quarter of the race – the first of which came after Jean-Christophe Boullion crashed the #13 Rebellion Racing Lola-Judd heavily in the Porsche Curves during Hour 14.
Disaster struck in Hour 17 for GTE Pro class leader Jan Magnussen – the former Formula One driver crashing the #74 Corvette while lapping the #63 Proton Competition Porsche heading into the Ford Chicane.
The incident handed the class lead to Toni Vilander in the #51 AF Corse Ferrari, which leads the #73 Corvette by a lap after the American machine was delayed thanks to an error from Olivier Beretta earlier in Hour 17.
Labre Competition leads the GTE Am class heading into the final phase of the race, with its #50 Corvette benefiting from the retirement of the #81 Flying Lizard Porsche.