Dean Stoneman maintained his Indy Lights championship push with a fourth place in Iowa keeping him just 23 points off the lead.

Rookie Stoneman was hoping to take some of his experience from his famous win in the Indy 100 at Indianapolis in May.

Heavy rain had put the race in doubt, but only qualifying was cancelled so championship positions determined the starting grid.

As the pace car went in at the start Stoneman maintained his second place and looked strong behind the lead car as he eyed up his third victory of his maiden season in the US.

But as the 100-lap race unfolded the 25 year-old from Bishop's Waltham suffered from under-steer.

He battled hard to hang on to second, but after a great duel with Zach Veach the talented Andretti driver slipped two places to fourth.

Stoneman closed the gap to within a second of third-placed Ed Jones, the Championship leader, in the final 20 laps.

But with back markers holding up his progress the Southampton-based driver was unable to claw back another place.

A frustrated Stoneman said: ”I feel like we missed a huge chance to make up ground in the championship.

"I struggled with under-steer from the start. I felt towards the end I could have got a podium place, but we had guys who were a lap behind us not helping our progress, which was really frustrating.

"We will go away and focus on the next round in Toronto.”

The Indy Lights Series moves to Toronto, Canada this weekend.