Switching from open-wheel racing to sports cars in 2007, Rojas joined Chip Ganassi Racing to compete in the Grand American Road Racing Rolex Sports Car Series, as a teammate to Scott Pruett. Claiming his first win in the series in 2007, Rojas won his first 24 Hours of Daytona endurance race the following year with co-drivers Pruett, Juan Pablo Montoya and Dario Franchitti. The victory propelled Rojas and Pruett to the Rolex Sports Car Series championship that year, setting a series record for the most victories in a season with six wins over the course of the year.