Road America IndyCar: Rossi leads every lap to take dominant win

The Andretti Autosport driver passed polesitter Colton Herta in the opening sequence of corners on the first lap and never looked back, leading all 55 laps and crossing the line almost 30 seconds clear of second-place finisher Will Power.

Power was comfortably ahead of Penske team-mate Josef Newgarden, who resisted a late charge from Graham Rahal to secure the final podium spot.

Scott Dixon completed the top five, fighting back from last place after he was pitched into a spin by Ryan Hunter-Reay on the opening lap.

Dixon took fifth on the final lap, breezing past a struggling Herta.

Herta eventually finished eighth after contending with a number of issues during the race.

After being passed by Rossi at the start, Herta was further held up by a fuel hose issue during his first pitstop, and then made contact with Simon Pagenaud on lap 21.

In the final laps, fighting with heavy worn tyres, Herta struggled to keep on track and had to fend off the Chip Ganassi Racing pairing of Dixon and Felix Rosenqvist, as well as James Hinchcliffe.

After initially repassing Hinchcliffe, who briefly got by, Herta lost out to Dixon, Rosenqvist, and Hinchcliffe once more in the space of a few corners.

Herta did however beat Indianapolis 500 winner Pagenaud, who fought back to ninth place after his earlier contact with the Harding Steinbrenner driver.

Takuma Sato rounded out the top 10, despite an early excursion over the grass after making contact with Hinchcliffe.

He bettered fellow early struggler Ryan Hunter-Reay, who took 11th, ahead of Sebastien Bourdais and Marcus Ericsson.

There was only one retirement in the race, with Marco Andretti's race ending on lap 20 when his car developed an electrical problem. He had been running in the top 10 before the problem arose.

Result - 55 laps

Drivers' standings