NBA Hall of Famer Charles Barkley waved the green flag over the inaugural Indy Grand Prix of Alabama.

Scott Dixon was ordered to relinquish third and fourth places to Hélio Castroneves and Marco Andretti respectively after being judged to have jumped the start.

The first yellow flag was displayed on lap 12 for Japanese ex-Formula One driver Takuma Sato, who stopped on-course in Turn 13 after a throttle failure.

Simona de Silvestro ran an impressive fifth, unable to keep pace with the top four but well ahead of sixth-placed Alex Lloyd.

The drivers who had pitted under the caution, including Power, Conway, Ryan Briscoe and Justin Wilson were all stuck in the mid-pack.

Ryan Briscoe finished sixth in the third Penske car, with Justin Wilson, Tony Kanaan, Mike Conway and Alex Tagliani rounding off the top 10.