Michael Shank Racing led the Daytona 24 Hours at one quarter distance with its Ligier-Honda JSP2.
AJ Allmendinger, who shares the car with Oswaldo Negri Jr, Olivier Pla and John Pew, held a one-second lead over the #31 Action Express Coyote-Chevrolet Corvette DP driven by Johnny Adam under safety-car conditions.
Brendon Hartley was running in third position in the #01 Chip Ganassi Racing Riley-Ford EcoBoost DP he shares with Alex Wurz, Andy Priaulx and Lance Stroll.
Fourth was the other Action Express Coyote-Chevrolet with Filipe Albuquerque at the wheel.
The Shank entry had moved into a clear lead during the fifth hour with Pla aboard after falling back following a double stint from Pew that included contact with the Extreme Speed Motorsports Ligier.
The car dropped out of the lead when it pitted as the end of the sixth hour approached, but was back in front with Allmendinger once the cars ahead stopped during the safety car period that quickly followed.
The ESM Ligier had led through the opening hour in the hands of Pipo Derani, but it lost time when the car was pushed into a spin by Pew after Johannes van Overbeek had taken over.
The DeltaWing took to the front with Katherine Legge on two occasions before the Elan/Mazda-powered DWC13 sustained serious damage when an unsighted Andy Meyrick ploughed into a stationery Prototype Challenge car at Turn 1.
The two factory Porsche 911 RSRs led the way in GT Le Mans with Frederic Makowiecki and Nick Tandy driving.
The Frenchman led his team-mate by just over a second, with the #100 BMW M6 GTLM a further second behind in Graham Rahal's hands.
The two Ford GTs had both run into transmission problems early in the race.
The #67 Ford, driven by Richard Westbrook, Ryan Briscoe and Stefan Mucke, was lying in 47th position and 22 laps behind the GTLM class leader having suffered two punctures as well.
The #66 car, shared by Joey Hand, Dirk Muller and Sebastien Bourdais, was in 51st position and 32 laps in arrears after also encountering a brake line issue.
The Prototype Challenge class was led by the PR1/Mathiasen squad and GT Daytona by the Paul Miller Lamborghini team.