Dane Cameron and Eric Curran raced to their second IMSA TUDOR United SportsCar victory of the year Sunday, leading Action Express Racing's 1-2 sweep at Road America.

Cameron took the lead in the No. 31 Corvette DP during a pit-stop cycle near the halfway point and only lost the top spot for three laps through the final pit sequence. Cameron finished 14.359 seconds ahead of Joao Barbosa in the No. 5 Corvette in the 2-hour, 40-minute race on the 4.048-mile circuit.

"These races, you have to be perfect to win, you're flat out for every single lap," Cameron said. "Every morning, when we have our pre-race meetings, the goal is to finish 1-2. It might have taken a few races to get there, but it's always the goal for each race."

Curran and Cameron also won at Detroit this season, and Cameron took a GT Daytona class victory two weeks ago at Lime Rock Park as a substitute driver with the Turner Motorsport team.

Richard Westbrook and Michael Valiante, fifth in the No. 90 Corvette DP, lead the Prototype standings with two races left — a point ahead of Barbosa and co-driver Christian Fittipaldi, and two in front of Curran and Cameron.

Bruno Junqueira got past Conor Daly on the final lap to take the Prototype Challenge victory in the No. 11 RSR Racing ORECA he shared with Chris Cumming. No. 911 Porsche North America teammates Patrick Pilet and Nick Tandy claimed their second consecutive GT Le Mans class victory, and Ben Keating and Jeroen Bleekemolen won the GT Daytona class in the No. 33 Dodge Viper.