Chip Ganassi Racing's Riley BMWs dominated the first hour of the 51st Rolex 24 at Daytona.
Scott Pruett and Scott Dixon ran one-two in the pair of Ganassi Riley BMW Daytona Prototypes as the race passed the hour mark, with five-time Daytona-winner Pruett holding an eight-second lead.
Polesitter Pruett, who shares his Riley with Memo Rojas, Juan Pablo Montoya, Charlie Kimball and Dixon, led from the start and increased his advantage to as much as 10s before the first round of pit stops.
Dixon, who also is entered in the second car alongside Dario Franchitti, Jamie McMurray, Joey Hand and Pruett, missed a gear at the start and dropped to fourth before making it back to second after 21 laps.
Michael Valiante ran third, 10s behind Dixon, at the end of hour one in the best of the Michael Shank Racing Riley-Fords, while Dane Cameron was fourth in the Team Sahlen Riley BMW. The best Chevrolet-powered car was the Wayne Taylor Racing Coyote in the hands of Max Angelelli in fifth place.
The MSR team's lead entry, which won last year's 24 Hours at Daytona, lost time in the opening hour while a suspension component was changed in the pits.
The GT category was led by Andy Lally in Magnus Racing's Porsche 911 GT3 Cup from Filipe Albuquerque in Alex Job Racing's Audi R8 GRAND-AM.
GT polesitter Nick Tandy led the opening laps, but pitted after just 15 minutes with heavy damage to the left-hand side of his Konrad/Orbit Porsche.
Following repairs, his co-driver Michael Christensen was running seven laps behind the class leader and 32nd in GT at the hour-mark.
Leading positions after 1 hour
Pos Cl Drivers Team/Car Time
1. DP Kimball/Montoya/Pruett/Rojas Riley-BMW 28 laps
2. DP Dixon/Franchitti/Hand/McMurray Riley-BMW + 8.102s
3. DP Cumming/Goncalvez/Valiante/Yacaman Riley-Ford + 18.762s
4. DP Cameron/Nonnamaker/Pagenaud Riley-BMW + 19.670s
5. DP Angelelli/Taylor/Hunter-Reay Corvette DP + 21.022s
6. DP Garcia/Gavin/Taylor/Westbrook Corvette DP + 25.844s
7. DP Allmendinger/Ambrose/Negri/Pew/Wilson Riley-Ford + 27.283s
8. DP Bourdais/Dalziel/McNish/Popov Riley-Ford + 27.909s
9. DP Davidson/Lamy/Minassian/Potolicchio/Sarrazin Corvette DP + 30.102s
10. DP Fogarty/Gidley/Gurney/Law Corvette DP + 33.725s