Favourite Golden Horn won the Coral-Eclipse Stakes under Frankie Dettori after fighting off The Grey Gatsby to seal a rare big-race treble.
The colt, trained by John Gosden, has triumphed in the Dante Stakes, the Derby at Epsom and Sandown's Eclipse.
Victory made it five career wins out of five, but Golden Horn was made to work by Jamie Spencer on the runner-up.
The Grey Gatsby came alongside him before Dettori went clear for a three-and-a-half length victory.
"I was in front and Jamie was very clever and attacked me early," said 44-year-old Dettori.
"He eyeballed me and this horse showed what a true champion he is. He showed a lot of guts to get the win in the end."
|Racing correspondent Cornelius Lysaght|
|Golden Horn was served up an examining test by the runner-up, who is a year older, as they duelled up the Sandown hill in what was, regardless of anything else, a fabulous horse race, but he got the upper hand in the most decisive of styles inside the final half furlong or so.|
|The Grey Gatsby might not have won this year, but there's no doubting his talent, so for the winner to retain his unbeaten record and complete the Dante/Derby/Eclipse hat-trick against such a reliable, older yardstick puts beyond doubt that the son of the stallion Cape Cross is the 'real deal'.|
Golden Horn, the 4-9 favourite, was slow out of the stalls, but soon pushed into an unaccustomed front-running role ahead of four rivals.
Last year's French Derby winner The Grey Gatsby (7-2) tracked the leader and they went head-to-head in the straight in a gripping duel, but Golden Horn ended a worthy winner.
Newmarket trainer Gosden said he would be guided by the horse over future engagements, but indicated the King George VI & Queen Elizabeth Stakes at Ascot (26 July) and the Prix de l'Arc de Triomphe at Longchamp (4 October) were possibilities.
"He's not in the Arc, he'd have to be supplemented. I think he'd be an Arc horse unless it went bottomless," he said.