The Aidan O'Brien-trained Deauville has claimed a first top-level success in the Belmont Derby in New York.

Jamie Spencer steered the colt to a neck verdict over Highland Sky in the hands in the $US1.25 million ($A1.67 million) race on Saturday (Sunday AEST).

O'Brien's assistant TJ Comerford said the return to a mile-and-a-quarter (2000m) was a key factor after Deauville finished down the track in the Epsom Derby (2400m).

"A mile and a quarter is probably his ideal trip," Comerford said.

"I saddled two good horses (stablemate Long Island Sound finished sixth), but the trip just worked out a little better for the winner.

"He finished stronger, had a good set-up and was left with plenty of run.

"The best horse won and he gave a great effort."

Catch a Glimpse extended her winning streak to eight and earned a return trip to the Breeders' Cup with her victory in the Belmont Oaks Invitational.

The Oaks was a Breeders' Cup Challenge race, guaranteeing the winner a spot in the $2 million Filly & Mare Turf on November 5 at Santa Anita.

Catch a Glimpse won the Breeders' Cup Juvenile Filly Turf last October at Keeneland in her usual front-running style.