Dean Stoneman claims his first US win in Indianapolis Indy Lights

The GP3 race winner and former Formula Renault 3.5 frontrunner, whose career had been interrupted by cancer after he won the 2010 Formula 2 title, left the European single-seater scene to work towards an IndyCar career this year.

The Indy race was unsettled from the beginning after Andre Negrao slammed into the outside wall on the main straight on the warm-up lap, meaning the first lap was under yellow conditions.

On the green flag polesitter Ed Jones couldn't maintain position while row two starter Felix Serralles missed the braking point at Turn 1, ran wide and interrupted the pack.

Zach Veach and European Formula 3 champion Felix Rosenqvist meanwhile tagged each other to rule themselves out of challenging for the front.

Stoneman made a charging start from fifth place up to the podium reaches, and had grabbed the lead Santiago Urrutia had inherited by the end of the first lap.

From there, the British driver was able to maintain a 0.7-second lead over Serralles.

Serralles looked the quickest driver on track and cut the gap to 0.3s, but a botched attempt to pass at Turn 1 with just a handful of laps remaining sent him hurtling down the order to fifth.

That left Urrutia in second and he hounded Stoneman to the finish.

But Stoneman was able to hold his fellow former GP3 driver to win with a 0.8659s advantage.

The result followed a frustrating third place finish for the Andretti driver in the first race of the weekend.

Stoneman had also made a strong start on Friday, sweeping through to third from his seventh place starting position, and briefly led amid a wild final lap battle with championship leader Jones and Urrutia before being pushed back.

RESULTS - 35 LAPS: