New Zealand IndyCar star Scott Dixon's title hopes took a dent with a sixth placing in the latest race in Pennsylvania.
The 37-year-old Dixon, seeking his fifth drivers championship, put in a competitive effort at the ABC Supply 500 at the Pocono Raceway on Monday (NZ time) but lost ground to his major rival.
Dixon went from third to second on the points table but series leaders Josef Newgarden (US) strengthened his grip on the title race with a second placing, increasing his advantage over Dixon from eight to 18 points.
There are three more races left in the season with attention now switching to Illinois next weekend and Dixon, a traditionally late charger in the championship, has work to do in a title race that is heating up.
Australian Will Power won in Pennsylvania to come into the frame.
American Alexander Rossi was third and defending IndyCar champion Simon Pagenaud of France was fourth to put pressure on Dixon.
Dixon, who was ninth off the grid did mange to finish one place ahead of Helio Castroneves and that saw him jump ahead of the Brazilian on the points table.
Dixon was in the mix throughout the race and was lying second when he made his final pitt stop to refuel with 23 laps to go.
He dropped to 13th and quickly fought his way back to sixth but couldn't make any further inroads.
"I think maybe we trimmed it too much at the end. It seemed that some of the other cars could run a bit closer," Dixon said.
"We moved up a spot but the 2 car (Newgarden) spread the championship a bit.
"We know St Louis is going to be a real tough one. Hopefully we can take something away from there and then finish strong at Watkins Glen and Sonoma."
Power overcame severe wing damage to claim the 32nd win of his career, which places him No 9 on the all-time list. He used clever defensive skills to keep a charging Newgarden at bay over the final few laps of an exciting race.
There were 10 leaders and 43 lead changes.
"I just knew that if he got up the inside that would be it. I was very conscious of protecting the inside," Power said later.
"He was very fast at the end there. What a day - I am spent. It was a seriously dramatic day but a lot of fun."