Ryan Hunter-Reay raced to his third IndyCar victory at Iowa Speedway in the last four years Saturday night.

Hunter-Reay held off the field on a late restart to give Andretti Autosport its sixth consecutive win on the 0.894-mile oval and its seventh in nine series races at the track.

Josef Newgarden was second and rookie Sage Karam was a career-best third, giving American drivers a sweep of the podium.

The last time Americans finished in the top three spots was the 2006 Indianapolis 500.

Points leader Juan Pablo Montoya's night lasted just nine laps after his No. 2 Penske car flew into the wall. His lead dropped from 54 points to 42 over Graham Rahal, who finished fourth.

Scott Dixon, who entered the race second in points, failed to capitalize on Montoya's misfortune. He finished 18th and fell to third, gaining just six points on Montoya.

Hunter-Reay, the 2012 series champion, had been among the more high-profile drivers to struggle with Honda's engine and aero kit this season. In fact, he hadn't finished higher than fifth all season.

But Hunter-Reay always seems to run his best in Iowa.

Hunter-Reay, who used fresh tires to get past half the field in the final 10 laps to win in 2014, clinched his 15th career win and gave beleaguered Honda its fourth victory in 13 starts this season.

For Montoya, the run of good luck he'd experienced all season finally came to an abrupt end.

It was only fitting that it happened at Iowa — again.

Montoya, who maintained his edge with top-10s in every race but one, lost control and hit the wall in the second turn, crushing the right side of Team Penske's No. 2 Chevrolet.

It ended a string of 18 straight races where Montoya was running at the finish.

Montoya last left a race early at Iowa in 2014 because of contact with 20 laps left.

"Something broke. As soon as I let it up, something gave out," Montoya said. "It sucks when it's completely out of our hands, when something fails."

Newgarden wound up second at Iowa for the second year in a row.

It wasn't a shock to see Karam have his breakthrough at Iowa, given that he'd won races here in four separate ladder series.

Karam did so with some maneuvering that left some of his competitors steamed. Ed Carpenter even confronted the rookie after a close encounter between the two, though the altercation didn't become physical.

"It's cool that Ryan won the race. He needed that. Americans kicked butt," Carpenter said. "(Karam) should have been penalized on the spot. He has no clue."