Treasure Beach continued the good run of form for Irish trainer Aidan O'Brien by lifting the Chester Vase.
Following Chester wins for stablemates Wonder Of Wonders and Await The Dawn, the Galileo colt held off the fast-finishing 6-4 favourite Nathaniel.
Jockey Ryan Moore said: "I had a nice spot. They went very steady early on and he travelled very well in behind.
"When he got half a gap he quickened up very well and when he got to the front he probably eased up a bit."
But the jockey warned he did not yet envisage the horse entering the Classic frame.
Moore added: "He'll have to improve to be a Derby horse."
Sent off at 7-2, Treasure Beach looked to be struggling behind Sadler's Risk as the field turned into the short straight, with Nathaniel looking well beaten at that stage.
To his credit, the 6-4 favourite found plenty when in the clear but Moore was in the perfect place to take advantage and struck by a head.
Treasure Beach had last been seen finishing 11 lengths behind Frankel in the Royal Lodge at Ascot.
Paul Smith, representing Treasure Beach's owners, said: "I have spoken to Aidan and he was delighted with that.
"As for the future, the two possibilities at the moment would be the Derby and Royal Ascot because he stays well. That was a good education round a tight, turning track."