Brazilian driver Helio Castroneves has claimed the Kentucky leg of the IndyCars series, with the series leader Will Power only able to finish eighth.
The Australian started on the front row and led for 86 of the 200 laps, but teammate Castroneves' fuel-conserving strategy paid off when the leaders had to make late stops for fuel.
Power had a scare when he narrowly averted a crash after his last pit stop, and the wobble means his standings lead has been cut to just 17 points, after the second-placed Dario Franchitti of Scotland crossed the line third.
The next race is two weeks away at Twin Ring Motegi in Japan, where Power has never raced and Franchitti has finished second and third in his past two visits.
The finale will be raced at Homestead-Miami Speedway next month.