Epsom Derby winner Golden Horn, ridden by Frankie Dettori, denied French mare Treve an historic third Prix de l'Arc de Triomphe with victory at Longchamp.
Dettori, winning the race for the fourth time, pulled Golden Horn wide early in the race before slotting in behind the leader.
They were well positioned before moving clear of Flintshire and New Bay, who finished second and third respectively.
Treve finished fast but had to be content with fourth.
"I really believed in the horse," said Dettori. "I was going so fast in the last 300 metres I knew no other horse would pass me.
"I had the best horse and I wanted to show how good he is. His record is unbelievable and he is probably the best horse I have ridden."
Golden Horn had already enjoyed a superb season with wins in the Derby, Dante Stakes and Coral-Eclipse - and bounced back from a shock defeat in the Juddmonte International to claim the Irish Champion Stakes.
The money earned for those victories meant the 120,000 euros (£88,600) owner Anthony Oppenheimer spent to add the John Gosden-trained horse to the field for the world's richest turf race was a relatively small price to pay.
|BBC racing correspondent Cornelius Lysaght|
|"Back on his favoured fast going, Golden Horn demonstrated his champion qualities here, qualities that led Frankie Dettori, who milked the occasion like only he can do, to suggest he's the best of all of his dozens of Group One winners (eight this season alone now). After such a year it's hard to argue with that.|
|"Trainer Criquette Head-Maarek offered no excuses for Treve, who retires as an undisputed superstar, though when asked for his verdict jockey Thierry Jarnet pointed straight at the ground.|
|"All the quality runners - Golden Horn, the reliable Flintshire, the French Derby winner New Bay, Treve, Erupt and Free Eagle - filled the first six places so you have to say a very good Arc won by a very good horse."|
The winning horse will head for stallion duties next season but could have one more run at the Breeders' Cup in Keeneland, Kentucky at the end of the month.
"The owner is quite keen on the Breeders' Cup. It gives us one day short of a month, he's got a great constitution and he travels well," said Gosden.
"If he's in good order next week, there's no reason why he can't go there.
"I keep saying he's a better horse coming from off the pace and he was today."