Ryan Hunter-Reay claimed victory in the ABC Supply 500 on Sunday, but Juan Pablo Montoya was a beneficiary in the IndyCar championship standings.

Hunter-Reay won for the second time in three races, clinching the 200-lap race at Pocono Raceway - which saw 12 cars, half the field, retire before the chequered flag.

And fittingly, Hunter-Reay won under a caution flag from Josef Newgarden and Montoya - who opened up a 34-point lead on Graham Rahal.

Rahal, a last-start winner at the Honda Indy 200, retired early on Sunday, but he remains well within sight of the title with double points up for grabs at the season-ending Grand Prix of Sonoma on August 30.

The Rahal Letterman Lanigan Racing man said he was keeping hope of reeling in Montoya in one week's time, but conceded the retirement was not ideal.

"We were working on it. We got it pretty good then we had an issue in the pits that lost us a bunch of spots and we were trying to work our way back up," Rahal said via indycar.com.

"This puts a big, big dent in things. We're down but not out."

The win was Hunter-Reay's 16th in his IndyCar career.

Montoya (500 points) can be caught by Rahal (466), Scott Dixon (453), Will Power (439), Helio Castroneves (423) and Newgarden (413).