MIAMI -- Emanuele Pirro and Frank Biela won the American Le Mans Series race in the Grand Prix of the Americas on Saturday, the team's third victory of the season.

It was the second straight victory for the Pirro-Biela team, which finished the 2-hour, 45-minute race on just one set of tires.

"We were afraid to lose track position by changing them under a yellow,'' Pirro said. "We took the gamble, and it was a gamble.''

The victory also secured the manufacturers' title for Audi, which won for the seventh time in nine events this season. Pirro and Biela had not won in four prior starts this season in which Biela was the fastest qualifier in the LMP900 class.

"The bad luck is gone now,'' Biela said. "We've proved that the performance is there and that we can win races.''

Cadillac had its best ALMS finish, with the team of Max Angelelli and J.J. Lehto placing second. Angelelli and Lehto started 17th in the 36-car field, but managed to weave their way steadily through the crowded field.

More history was made in the GT series. Sascha Maassen tied Olivier Beretta atop the career ALMS victory list, teaming with Luhr for the win. It was the 14th career win for Maassen, who has won six times with Luhr in 2002.

Claudia Huertgen, the polesitter in the LMP675 class, teamed with Chad Block for their second win of the season. Block, who relieved Huertgen at the race's midway point, took the lead after Michael Durand hit the wall with about 35 minutes remaining.

"Claudia gave me a good car to drive, and the rest was easy,'' said Block, who finished six laps ahead of anyone else in 675 class, the largest margin of victory in any level of the series Saturday.

In the GTS series, Ron Fellows and Johnny O'Connell also earned their sixth win of the year, edging fellow Corvette drivers Kelly Collins and Andy Pilgrim. The Collins-Pilgrim team endured a stop-and-go penalty early in the race, proving especially costly.

The ALMS event was the weekend co-feature in the Grand Prix, sharing top billing with Sunday's CART race on Miami's 1.387-mile road course.