A 'rookie mistake' by Scott Dixon has seen him cough up a chance to all but close out the Indycar title.

Dixon was sitting second in today's race at Mid-Ohio when he went too wide on a corner and ended up in the grass. That saw the Kiwi drop all the way back to 20th, giving up any chance of a fifth victory this season.

Dixon managed to fight his way back to finish 10th, the same spot he claimed in the weekend's first race. He arrived at the track with a chance at mathematically clinching his sixth IndyCar championship with a strong weekend but instead had an unusually poor showing. He qualified 17th for yesterday's race and couldn't make up enough positions to stop Josef Newgarden from slicing 20 points from his 96-point lead in the standings.

His lead in the overall standings now sits at 72 points with just three races remaining.

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The Chip Ganassi Racing driver admitted he made a 'stupid mistake' to end up at the back of the field.

"Got a little bit aggressive. Hit the over-take on the exit to one and just way too much Honda power there and it spun the tyres and spun the car," Dixon said after the race. "Totally caught me off guard. A total rookie mistake. I'm bummed for the team. It was such a stupid mistake I shouldn't have made."

He still leads the Indycar standings with three races remaining but a victory today would have all but secured his sixth title.

Colton Herta won the race, his first victory of the season. He led teammates Alexander Rossi and Ryan Hunter-Reay in a sweep for the Andretti group.

"It's so huge. So huge," team owner Michael Andretti said. "Man, 1-2-3, after the way things have been going for us this year, this is huge."

Josef Newgarden, who sits second behind Dixon in the season standings, was eighth.

Racing returns in October with another double race weekend at the Indycar Harvest GP in Indianapolis followed by the season-ending Firestone Grand Prix of St.Petersburg.