Indianapolis road course IndyCar: Power holds off Rahal for win

Power started from pole and led 65 of the 82 laps, conceding the advantage only when the pitstops were cycling through.

However he spent the final stint working to strike a balance between saving fuel and maintaining a gap to Rahal, who had popped up in second after staying out a lap longer than the leaders in his first stint.

The battle between the Penske and Rahal Letterman Lanigan drivers came to life in the final stint. Power had a 4.2-second lead over Rahal, but had less wiggle room with his fuel mileage.

That allowed Rahal to slash the gap down to just 1.5s in the space of six laps, but a combination of lapped traffic and improving fuel numbers gave Power the opportunity to reclaim some of the lost time, and he crossed the line 2.3s clear of his pursuer.

"That was hard when he [team president Tim Cindric] told me the [fuel] number I had to get and then told me 'Rahal's closing and is 0.8s quicker than you right now,'" said Power.

"I tried to save fuel in the spots where we'd not lose time and push in other areas.

"I think that was the most physical race I've ever won. I was so determined to win."

That Rahal was even in the position to harass Power owed a lot to a mess at the first corner.

It began when Scott Dixon, who had started alongside Power on the front row, was tagged into a spin by Helio Castroneves.

The concertina caused another clash further back between James Hinchcliffe and Barber winner Josef Newgarden, who completed his misery by stalling, and sent several other cars wide through the grass as they attempted to avoid adding to the carnage.

Rahal was one of the biggest beneficiaries of the whole thing - in the space of a couple of corners he shot from 17th to fifth - although he conceded later that he didn't have the outright pace he needed to catch Power.

"I've got to give it to my guys," he said. "The pitstops were good and we were able to make some moves when we had to.

"We weren't the quickest today, and when we were it was just because we had a clear track.

"I gave it everything I can to catch Power but he had a little bit too much."

Juan Pablo Montoya had Rahal in his sights for a while before backing off in the final stint to save fuel, and he spent the closing laps making sure that he remained ahead of Sebastien Bourdais. He was successful, and goes into the Indy 500 having fractionally extended his lead in the championship.

Castroneves did well to recover from the opening lap fracas to finish sixth behind Charlie Kimball, while Dixon, who was further delayed after the crash by the need for a new rear wing, fought back to 10th.

Defending race winner Simon Pagenaud was running in fifth place behind Montoya and Bourdais when he was forced to retire with a mechanical problem.

RESULTS - 82 LAPS:

CHAMPIONSHIP STANDINGS: