SEBRING, Fla. – Marco Werner overcame a punctured tire to build a one-lap lead halfway through the 55th annual 12 Hours of Sebring on Saturday.

Frank Biela was at the wheel of the No. 2 Audi R10/TDI when he had a tire puncture, made his way slowly back to the pits and fell two laps behind during the second hour of the American Le Mans Series' season-opening event.

But Biela, Werner and Emanuel Pirro made up the lost time within two hours, aided by a stop-and-go penalty assessed against No. 1 Audi R10/TDI driver Tom Kristensen for bumping into Butch Leitzinger's Porsche RS Spyder entering the pits.

In the fifth hour, Allan McNish was leading in the No. 1 Audi when he pitted, only to lose four laps while his pit crew replaced the battery and then the starter. That gave the lead back to Werner, and McNish fell back to seventh.

The race was developing into a battle between the Audis and a fleet of new LMP2 prototypes from Acura and Porsche in America's oldest sports car race. The smaller, less-powerful LMP2 cars took the lead six times during the first five hours as the Audis were forced to pit earlier for fuel. The faster Audis never were able to build up a large lead on the 3.7-mile road course.

Acura's Dario Franchitti, on loan from Andretti Green Racing's IRL team, was second overall and first among the LMP2 cars at the halfway point. Dyson Racing, which switched from LMP1 to a Porsche RS Spyder LMP2 during the offseason, was third at the midway point with Andy Lally behind the wheel.