New Zealand driver Scott Dixon claimed his second Indycar Series title with a dramatic second place finish in the Peak 300 at Chicago.

In the closest finish in Indy racing history, Dixon was pipped by 0.001 seconds by Brazilian Helio Castroneves, the only man who could have denied the New Zealander the overall crown.

However, Dixon had to finish lower than eighth at the Chicagoland Speedway oval to lose his series lead and, after an awkward afternoon, he comfortably did what was needed.

There was no repeat of the heartbreak last year when Dixon had the title within his grasp in the last race at the same venue before running out of petrol on the penultimate bend.

“I still can’t believe it, what a race,” Dixon told ESPN straight afterwards.

“We were back and forward, we got shuffled back a little bit. Some of the guys I wouldn’t expect were racing super fast today.”

The result capped an incredible year for the Target Chip Ganassi Racing driver, who won the prestigious Indy 500 in May.

“My year in general, getting married to my beautiful wife Emma and having the season that we’ve had has been amazing.”

Castroneves, who started 28th and last on the grid after being penalised in Sunday’s qualifying, surged through the field to lead before the halfway point of the 200-lap race.

Conversely Dixon, who started second, dropped to as low as 10th when the race restarted after a caution on lap 109.

“When you’re racing around 10th you’ve got people in front of you, people behind you, it’s really tough,” he said.

“To try to keep yourself calm and know you’ve got the car to get to the front was the hardest part.”

Dixon last won the series in 2003, when it was known as the Indy Racing League.

He has endured all manner of frustration since, including last year’s last-gasp failure which had haunted him.

Dixon revealed pre-race that he had endured a disrupted buildup, having taken one of his dogs to the vet because it was suffering from ear ache.

“It was a bit of a pain but luckily enough the dog’s doing well and we’re all happy.”

Dixon set a host of Indy racing records.

He equalled the most race wins in a season of six and broke the record for the most laps led in a season.