Kyprios beat Trawlerman in a thrilling Gold Cup duel at Royal Ascot to become only the third horse to regain the title.
The 2022 winner, who missed the race with a serious injury last year, prevailed by a length under Ryan Moore for trainer Aidan O’Brien.
Kyprios, sent off the 11-10 favourite, came out on top after a gripping battle up the home straight, with Sweet William in third.
It was a ninth win in the week’s biggest race for O’Brien, who was described as a “genius” by Michael Tabor, one of the winning owners.
Kyprios hit the front approaching the final furlong and fended off the challenge of Trawlerman, under William Buick for John and Thady Gosden.
“He’s more value than his winning distance,” said Moore.
Trawlerman had beaten Kyprios on softer ground at Ascot on British Champions Day in October.
“That’s what you like to see – a ding-dong right to the line at the end of a Gold Cup. Having nailed him on the mud, Kyprios beat us on the fast ground today,” said John Gosden, who also trains Sweet William.