British raider The Grey Gatsby and Ryan Moore caused a turn-up in the Prix Du Jockey-Club, the French Derby, at Chantilly.
The Dante Stakes winner appeared to get warm before the start and was also squeezed out in the early scrimmaging for position which saw drop to the back of the 16-runner field.
However, Moore moved towards the rail, made steady progress up the inside of his rivals throughout the final half-mile and found a perfect opening approaching the final furlong.
The Grey Gatsby, sent off at 19/1 on the Pari-Mutuel, quickened when asked and shot clear at that point, leaving his rivals toling. He scored by three lengths.
The Alain de Royer-Dupre-trained Shamkiyr stayed on for second place, just ahead of never-nearer favourite Prince Gibraltar who like the winner was held up in the early stages, but unlike the winner failed to find the gaps opening when he needed them in the home straight and finished fast but too late to land a blow in a rough race.
The other British raider Ayrad was only 11th. The French Guineas winner Karakontie appeared not to stay and finished eighth.
It was a first Classic for Ryan, a first victory in the race for Moore and was achieved in the fastest time since the race was reduced in distance in 2005 - the same year of the previous British-trained winner of the race, Godolphin's Shamardal.
Ryan said: "We always thought he was a good horse and after the Dante Ryan thought that the French Derby would be the right race for him.
"I don't think he got the credit he deserved after the Dante Stakes. Obviously it's great to win a French Classic.
"He will have a break now for a couple of weeks and then there would be the Juddmonte International to consider."
Asked if he thought the horse would stay further, Ryan said: "I don't see any reason why he wouldn't stay. He doesn't have an entry in the Arc, but yes, we would consider supplementing him."
Owner Frank Gillespie was overwhelmed, and said: "It's great to win this race, it means a lot to us. I have about six horses in training with Kevin and I would like to thank Ryan who rode him so well today. I think I would like to go to York with him next."
Moore explained his strategy when he said: "This is the second time that he has run over this trip and he won really well.
"He broke well and as usual it was a bit messy early on with everyone trying to get off the rail and I actually went back to the rail.
"Once he got his position he found his rhythm and when we got into the straight I thought he would win. He showed a good turn of foot."
Jean-Claude Rouget is likely to step Prince Gibraltar up in trip for next month's Grand Prix de Paris over a mile and a half.