Solemia denied Japan a first victory in the Qatar Prix de l'Arc de Triomphe as the filly got up in the last strides to beat Orfevre in a thrilling renewal at Longchamp.
Everything appeared to have gone to plan for Orfevre, who carried the weight of a nation's hopes.
Christophe Soumillon dropped the Far East challenger right out at the back, but he came cruising through in the straight and went at least two lengths clear of Solemia, even trading at 1-100 at one stage on the betting exchanges.
However, Carlos Laffon-Parias' four-year-old showed incredible guts under Olivier Peslier to give the rider his fourth win in the race. Masterstroke was third.
Solemia was last seen finishing third behind Shareta in the Prix Vermeille but that one never showed up at all in the testing ground.
Camelot, Aidan O'Brien's 2000 Guineas and dual Derby winner, was given every chance by Frankie Dettori and briefly threatened but emptied out close home. He eventually finished seventh.
Orfevre had broken from stall 18 and made up a tremendous amount of ground but became yet another agonising defeat for Japanese racing after El Condor Pasa, Deep Impact and Nakayama Festa.
Afterwards, Laffon-Parias said of the winner: "She had a hard first part of the season so we gave her a two-month break and started to prepare her for the Arc.
"Soft ground is very important to her, but Olivier made the difference. I hoped she might get a place and obviously this is much better." - Carlos Laffon-Parias
"Soft ground is very important to her, but Olivier made the difference. I hoped she might get a place and obviously this is much better."
Laffon-Parias went on: "It's a big day for me to have all my family with me. It's my third runner in the Arc, but the first that I've had with a chance.
"Sometimes the jockey can make the difference and Olivier Peslier is the one who won the race.
"To be honest I think the fillies are better than the colts and the older horses are better than the three-year-olds.
"People were saying Camelot was unlucky in the St Leger and maybe it was the jockey's fault but the winner of the St Leger is not really a Group One horse and maybe Camelot is not that good."
Pierre-Yves Bureau, racing manager for the winning owners, said: "It's just magnificent. She's such a nice, big filly and Olivier rode a perfect race - that's why you have a big jockey in a big race.
"I'm very pleased for the Wertheimers because of the investment they have made in racing over the years."
O'Brien said of seventh-placed Camelot: "It was very sporting of the lads to let him run, but he wants fast ground. Joseph (O'Brien) has always said he is a better horse on quicker ground and it's been a long, hard season.
"He's also come back minus two or three shoes.
"He's something for us to look forward to next season, as he will remain in training. Hopefully he has a good winter and he could be something unbelievable next year.
"As far as St Nick is concerned, he will now go to Santa Anita for another crack at the Breeders' Cup."
Dettori said: "It was just a long season took its toll. I had a perfect trip and he took me beautifully into the straight on the bridle, but just as soon I knew we were in trouble and in fairness to the horse he's been going for some time since the Guineas."