New Zealander Scott Dixon has endured an error-ridden second race at Mid-Ohio to finish tenth.
The result sees Dixon's overall championship lead reduced to 72 points just ahead of Josef Newgarden, who crosses the line into eighth.
The Chip Ganassi driver was in third until he clipped grass on lap 22, spinning out of control.
The error saw Dixon drop to 20th position and forced him to take drastic action as he tried to salvage something out of the race.
"Total rookie mistake. I'm so bummed for the team, just such a stupid mistake I shouldn't have made," said a disappointed Dixon.
"Obviously the car was faster and I was able to fight our way back but should have been easy points today."
At the other end of the race, young American Colton Herta drove to victory.