Hot favourite Caravaggio was bitterly disappointing as Kevin Ryan's Brando claimed Group One glory in the Prix Maurice de Gheest at Deauville.
Brando kicked off his campaign with victory in the Abernant Stakes at Newmarket in April and although he was down the field in the Duke of York, he bounced back to finish third in last month's July Cup.
Making his first appearance in France, Brando travelled powerfully in the hands of Tom Eaves and was produced to challenge Signs Of Blessing for the lead in the final furlong.
Ryan's charge saw out the six and a half furlongs well to hold off the late charge of fellow British challenger Aclaim, trained by Martyn Meade. Richard Hannon's Tupi was a clear third.
The Aidan O'Brien-trained Caravaggio lost his unbeaten record when fourth in the July Cup and was odds-on to return to winning ways.
However, he made a tardy start and never threatened to land a telling blow, having to settle for sixth in a tight photo for fourth place, which went to the Charlie Hills-trained Magical Memory.
Ryan had to shut down his yard completely in early June for a few weeks after one of his horses tested positive for Equine Herpes.
"It's a great day. We're delighted with the horse," said the Hambleton-based trainer.
"He ran a good race in the July Cup and he'd tightened up since. He got a great ride and he was exceptional today."
O'Brien felt the race may have come too soon for Caravaggio, saying: "Maybe I ran too close after Newmarket."