Favourite Afleet Alex was an impressive winner of the Belmont Stakes in New York on Saturday.
The horse, which had also won the Preakness Stakes this season, finished seven lengths clear of Andromeda's Hero with Nolan's Cat taking third.
Pinpoint and and Giacomo - the winner of the other leg of the USA's big three-race series the Kentucky Derby - were contesting the lead early on.
Afleet Alex, ridden by Jeremy Rose, took control in the final quarter mile.
"I had the best horse and I had the fastest quarter mile when I needed it," said Rose.
Winning trainer Tim Ritchey added: "When Jeremy asked Alex to run, he exploded."
Giacomo, a horse expected to challenge for the crown, finished down in seventh.