Simon Pagenaud held off Scott Dixon to secure victory at the Grand Prix of Long Beach on Sunday in controversial circumstances.
As Pagenaud left the pits following his second stop the French driver cut the pit exit line, managing to pass Dixon in doing so before going on to claim the chequered flag.
Indycar reviewed the incident but gave Pagenaud just a warning, confirming his fifth-career win in the series and a first driving for Team Penske.
The win also extended Pagenaud's lead atop the drivers' standings over Dixon to 14 points following his second-place finishes in St. Petersburg and Phoenix.
Chip Ganassi driver Dixon attempted to find a way past Pagenaud in the closing stages but the defending champion had to settle for second behind the 31-year-old.
Helio Castroneves dominated the early part of the 80-lap race on the streets of Long Beach but after being held up by Jack Hawksworth the Brazilian could only manage third.
Former Formula One drivers Juan Pablo Montoya and Takuma Sato rounded out the top five in California.