Kieren Fallon sealed a Longchamp treble with victory on Hurricane Run for his first Prix de l'Arc de Triomphe win.
Fallon surges for home on Hurricane Run
The Andre Fabre-trained 11-4 favourite stormed ahead in an exciting finish to win by four lengths from Westerner, with last year's winner Bago in third.
Earlier, Fallon and trainer Aidan O'Brien enjoyed double success, first with 2-1 favourite Rumplestiltskin in the Prix Marcel Boussac.
He then won on O'Brien's Horatio Nelson in the Prix Jean-Luc Lagardere.
Irish Derby winner Hurricane Run showed his class in the day's big race after a start which left him with plenty to do.
But he surged to victory on the rails from a furlong out.
Fallon said: "He got shuffled back at the start, I didn't really want to be that far back and it got very rough turning for home.
"But I was lucky enough to have a horse to get me out of trouble.
got a dream passage on the rails to lead with a furlong to go in the big race of the day.
Victory for the three-year-old colt on soft ground gave French trainer Fabre his sixth Arc success.
Fabre said: "You can't compare winners as every horse is different. He is special - he is an Arc winner."
Fallon persuaded Horatio Nelson (4-7 fav) to dig deep for victory in the Prix Jean-Luc Lagardere (Grand Criterium).
He had the Danehill colt in the front rank throughout and it was left to British raider Opera Cape to throw down a strong challenge.
The pair were neck and neck coming into the final furlong and Opera Cape looked to just get his head in front at one point before Horatio Nelson found an extra gear to win going away.
Fallon guided Rumplestiltskin to success
Fallon and O'Brien's first success of the day came with Rumplestiltskin in the Prix Marcel Boussac.
Fallon clinched victory with a well-timed run to take Quiet Royal close to home.
Deveron, trained by Clive Brittain and ridden by Kieren McEvoy, stayed on well for third place.
Kinnaird landing a surprise victory for trainer Pat Haslam and jockey Kevin Darley in the Prix de l'Opera.
Darley, successful on Peeress in the Sun Chariot Stakes at Newmarket on Saturday, had Kinnaird (33-1) well placed all the way.
The four-year-old, who had not won for two seasons, gamely held off Mona Lisa and hot favourite Alexander Goldrun.
Roger Charlton crowned a magnificent weekend with an amazing one-two with Avonbridge and Striking Ambition in the Prix de l'Abbaye.
The trainer, who won the Cambridgeshire with Blue Monday at Newmarket on Saturday, also had Patavellian finish a close fifth.
Striking Ambition looked set to score when taking over from Fire Up The Band, who had set a scorching pace, but Avonbridge (10-1) stormed home under Steve Drowne to win by a short neck.
The David Nicholls-trained Fire Up The Band was third another length-and-a-half back from Striking Ambition.
Prix de l'Arc de Triomphe, Longchamp. 1m 4f
1 Hurricane Run 11-4
2 Westerner 16-1
3 Bago 8-1
(A Fabre) K Fallon
15 ran. Dist: 4l