The Team Penske driver went into Sonoma as the title favourite, but was dealt a blow when he and team-mate Will Power collided just after a restart, dropping both to the back of the field.

In the meantime, Dixon had worked his way to the front, meaning that Montoya had to recover to at least fifth place in order to secure the championship.

He finished sixth, consigning him to runner-up, but insisted that unnecessary variables, including the double-points format and a new-compound tyre, were to blame rather than the contact with Power.

“We had a good car,” Montoya said. “We had a good start, and we did everything we needed to do at the beginning.

“Will overshot, we shot the corner, we got inside and [Power] cut across and I was there, and we touched and that was it.

“We came from behind and did our best, just wasn’t enough.

“It’s tough there; tyres are going off, and it’s one of those days.

“It sucks, but when you make the last race double-points on a road course and you change the tyre and you do everything you did for this weekend and you put so many variables, it doesn’t even matter what you do all year.

“Dixon had a shit season all year and had one good race, and we paid the penalty.”

Montoya hopes IndyCar reconsiders the double-points system in the future, although he conceded that he holds little hope that it will be changed.

“We’ll see if they [IndyCar] change it, but they like the excitement for the last race,” he said.

“Is it fair? No, but we go into the last race of the year knowing it’s a double‑points race.

“Is it fair for a normal championship? No, it’s not fair, but it’s the rules they want to play with, and if you don’t like the rules, don’t race.”