Cirrus des Aigles won the feature Qipco Champions Stakes at Royal Ascot, holding off the 7-4 favourite So You Think this afternoon.
The French horse just came through in the £1.3m race during the inaugural British Champions Day.
Christophe Soumillon drew Cirrus des Aigles level in the latter stages and held off Ryan Moore's charge on New Zealand's So You Think.
Cirrus des Aigles' Trainer Corine Barande-Barbe said: "This means a lot because I always thought he was very good.
"To win a Group One against the best horses in England is fantastic."
The French horse's run also set a new course record over 10 furlongs.
"This is the best day I've had in racing. Thank you to all the British people who have welcomed us," Barande-Barbe added.
Earlier in the day revered colt Frankel maintained his unbeaten record, easing to victory in the Queen Elizabeth II Stakes.