Tracy took advantage of Brazilian Bruno Junqueira'sinability to score any points, thanks to a 13-place finish in the 92-lap race. Junqueira was the points leader but now trails Tracy, 184-164, with six races remaining.
Tracy earned his career-best sixth win this season and 25th career. He won the other Canadian stops at Toronto and Vancouver.
Michel Jourdain Jr. of Mexico was fourth for the third time this season. Frenchman Sebastien Bourdais, a teammate of Junqueira at Newman/Haas Racing, established a series record by becoming the first rookie ever to score five consecutive top-five finishes. He placed fifth.