Will Power claimed a fourth win his last six races to gain significant ground on Simon Pagenaud after the championship leader crashed in Monday's rescheduled IndyCar race at Pocono.
Power finished second behind Penske team-mate Pagenaud at the Honda Indy 200 at Mid-Ohio last month, but racked up another victory in a ABC Supply 500 which was postponed on Sunday due to heavy rain.
The Australian now trails Pagenaud by only 20 points heading into the Firestone 600 this weekend after holding on for another win at Pocono Raceway.
Pagenaud paid the price for a crash at turn one which prevented him from finishing a dramatic race, with Schmidt Peterson Motorsports' Mikhail Aleshin taking second place.
Aleshin led for 87 laps, but was unable to seal the win as he was runner-up ahead of Andretti Autosport's Ryan Hunter-Reay, who started on pole for the first time in his IndyCar career.
There was relief when Alexander Rossi, Charlie Kimball, and Helio Castroneves walked away from a pitlane crash.
Rossi and Castroneves had to retire from the race after the former's car landed on top of the latter's following a collision with Kimball.