Creator has pulled off an upset win in the Belmont Stakes, closing fast to claim Destin by a nose.

The Steve Asmussen-trained colt was unplaced in the Kentucky Derby and did not run in the Preakness Stakes but relished the extra distance (2400m) in the final leg of the Triple Crown series on Saturday (Sunday AEST).

Preakness winner Exaggerator was the 7-5 Belmont favourite but weakened after being up close early in the race.

Ridden by Irad Ortiz jr, Creator went out at 16-1 while Japanese colt Lani, who finished ninth in the Derby and fifth in the Preakness, ran a strong third.

"I'm glad to see him put that number up," Asmussen said.

"Irad gave him a dream trip. The horse ran super."

Kent Desormeaux, the Hall of Fame rider aboard Exaggerator, second-guessed his decision to ask his colt to wait behind a slow pace. When he tried to make a move, Exaggerator, trained by his brother, Keith, just didn't have it.

"I don't know it there would have been any difference in the outcome," he said. "When I picked him up at the quarter-pole (400m) to try and win the race, there was nothing there."

Asmussen will soon be inducted into the Hall of Fame.

He has won the Preakness twice, with the filly Rachel Alexandra in 2009 and Curlin in 2007.