Power claimed victory in the iconic American race by just over three seconds, having assumed the lead with a handful of laps to go when Oriol Servia, Stefan Wilson and Jack Harvey all were forced into the pits for fuel.

It was a perfectly judged race from Power’s team, Team Penske, while on the track Power was clearly the quickest driver for most of the second half of the race. He led 59 of the 200 laps

The Australian, who has suffered multiple disappointments in this race over many years, could hardly contain his emotions – even before he crossed the finish line.

"On the white flag lap, I started screaming because I just knew I was going to win it," he said. "Unbelievable! Never been so excited."

"This month was one of the best months I've had. Very relaxed, in tune with my engineer, just working really well. It just came together."

Power's first Indy 500 win was also the 17th Indy 500 win for Team Penske.

"He won this race today because he was the best," team owner Roger Penske said.

"This closes the book for what he wanted to accomplish in Indycar: win a championship (2014), now is tied for winning the most races as an Indy driver for the team (31) and the Indy 500 is something that he wanted to do from the very beginning... He's in a different world right now, which is important."

Fellow Australian James Davison had a difficult race, struggling on an unseasonably hot day when many drivers found it hard to tune their cars for optimum handling. In a crash-filled Indy 500, Davison prompted the first yellow flag caution period when he slowed and was hit by last year’s Indy 500 winner, Takuma Sato.

Power's win made it an unprecedented weekend of success on the international stage for Australian drivers, with Daniel Ricciardo having won the Monaco Grand Prix only a few hours earlier.