Castroneves took the victory Sunday in the inaugural series race at Barber Motorsports Park because Power, who had won the season’s first two races, got caught with the wrong pit strategy.
Castroneves completed the Indy Grand Prix of Alabama in two stops; Power needed three.
Power had won the races in Brazil and St. Petersburg, Fla. He still holds the points lead because he finished fourth.
Castroneves won his first race since last year at Texas Motor Speedway. Scott Dixon finished second with fellow Ganassi Racing teammate Dario Franchitti third.
“It was the worst possible lap to make a decision to pit,” Power said of the lap 14 call. “It could go one way or another, and we went the other.”
Dixon was irritated with the Indy Racing League’s decision to make him give back two positions at the start of the race. Dixon blamed Power for too slow of a start.
“It’s the first time I’ve ever started a race in first gear,” he said.
Dixon said he didn’t pass the car in front of him, which was Castroneves, the third-place starter.