The Piston Cup is the fictional race championship in Pixar's first Cars movie. Lightning McQueen competes in the series as a rookie, and the championship drives the film's opening and closing racing story.
The Piston Cup is modeled on the culture of American stock-car racing, especially its oval tracks, sponsor liveries, pit crews, and season-long points competition. McQueen begins the film tied with veteran racer The King and Chick Hicks, creating a three-way contest for the championship.
After McQueen causes problems while traveling to the final race, he becomes stranded in Radiator Springs. His experiences there teach him that winning is not the only measure of achievement. He still returns to the Piston Cup finale, but his behavior and priorities have changed.
The Piston Cup is different from the World Grand Prix in Cars 2. The World Grand Prix is an international event created for the sequel, while the Piston Cup is the recurring American racing championship associated with McQueen's original career.