SONOMA - New Zealand’s Scott Dixon snatched his fourth IndyCar Series Championship with a dramatic victory in the season-ending Grand Prix of Sonoma in California on Sunday as Juan Pablo Montoya’s title dreams ended in disappointment.

Chip Ganassi Racing driver Dixon pipped Penske rival Montoya to the title on countback after the two rivals finished the season locked on 556 points for the title in a thrilling end to the season. It was a remarkable comeback by Dixon, who took advantage of a crucial blunder by Montoya midway through the race when the Colombian clipped team-mate and fellow title hopeful Will Power to leave both men way down the field. “I still can’t believe it, it was such a long shot,” said a jubilant Dixon, who had started the day 47 points adrift of Montoya in the championship standings.

It was a bitter end to the season for Montoya, who had led the IndyCar Series standings all season and who had looked poised to win his first championship crown. Montoya could barely conceal his disappointment, refusing to dwell on the key moment when he collided with Power. “It doesn’t matter what happened,” Montoya said. “We fought all year. It’s just a shame. We just threw it away. We had a competitive car today to do what we needed to do but just couldn’t close it out. “It doesn’t matter — we had one bad race where it’s double points and we’re out of the championship.”

Power meanwhile bemoaned the fact that the various yellow and green flags had bunched the field and shaped the outcome of the race.

“I feel horrible for Juan,” Power said. “We were all in good shape. “But we’ve got to decide whether we’re a sport or a casino. The championship shouldn’t be decided by race control.”

Dixon’s title was his fourth to set alongside IndyCar Series crowns from 2003, 2008 and 2013. Sunday’s race had got under way with the IndyCar world still struggling to come to terms with the tragic death of British driver Justin Wilson, who died on Monday after suffering a serious head injury at Pocono Raceway a day earlier.

Drivers from all teams lined up for an emotional pre-race tribute to Wilson, linking arms in a line in the pit lane to pay respects to their fallen fellow driver while a rendition of the British national anthem was played. When the racing got under way on the 2.385-mile (3.84-kilometer), 12-turn road course, Power and Montoya’s championship hopes were firmly afloat nearing the halfway stage.

However the pivotal moment of the race came on lap 39 of the 85, when Montoya struck Power after attempting to take advantage of an inviting opening.

The collision saw Power spin off and caused damage to Montoya’s front wing, forcing both men back into the pits and leaving them way down the field mired in the back markers. A green flag with 12 laps to go bunched the field to give Montoya a glimmer of hope as the Colombian lay in eighth spot, needing to finish in the top five to take the title.

But with Montoya’s tires deteriorating the Colombian was always struggling to move up the field as Dixon held onto first place. Montoya advanced to sixth following Sebastien Bourdais’s crunching shunt into the rear of Graham Rahal, but was just unable to move one place further up the field which would have given him the title.