Mexico's Pato O'Ward won Sunday's IndyCar Salute to Farmers 300, capturing his fourth career title and second of the year after long-time leader Josef Newgarden crashed late in the race.
O'Ward took the lead when Newgarden crashed out due to a suspension failure then kept it after a final pit stop under caution in the 300-lap feature on the 0.894-mile oval at Newton, Iowa.
O'Ward surged ahead on a restart with 50 laps remaining and stayed in front to the finish with Australian pole-sitter Will Power second, New Zealand's Scott McLaughlin third, New Zealand's Scott Dixon fourth and American Jimmie Johnson fifth.
"Super stoked. Super happy," O'Ward said. "It was all about capitalizing and being there when we needed to be."
Indianapolis 500 winner Marcus Ericsson of Sweden, who finished sixth, kept the season points lead 403-395 over Power with Newgarden and Dixon 34 points behind and O'Ward 36 adrift.
"We're still in the lead and now we're going to tracks where we know we're strong, so I'm happy about that," Ericsson said.
Newgarden started second and led 148 laps but his race ended with 65 laps remaining with a crash in the fourth turn, the American losing control low and spinning into the outer wall.
Newgarden, who was unharmed, was near the first IndyCar weekend sweep in five years.
"I want to cry," Newgarden said. "So sad for my team. I don't know what happened. I didn't know it happened until I was in the wall."
After being the season points runner-up the past three years, he was also in position to grab the points lead when he crashed.
Newgarden won his fourth race of the season, and fourth race in Iowa, on Saturday.
Power settled for his second podium of the weekend and sixth of the year.
"You'd love to get the win. Still a good day," Power said. "We were really fast. Good to be on the podium and close on the points lead."
Dixon, a six-time season champion, edged closer on the points list in his 300th consecutive IndyCar start.
"The top three were pretty quick," he said. "Good points day for us."
Former US stock car icon Johnson had his best IndyCar finish.
"This is a really special day for me," he said. "I really felt like a podium was within our reach."
Power can match Mario Andretti's all-time record of 67 IndyCar pole positions next Friday on the Indianapolis Motor Speedway road course in qualifying for next Saturday's 13th of 17 season races.
The Aussie has won six poles on that track.