Study of Man took the lead in the final furlong and held off several challenges to win the Prix du Jockey Club, the French Derby, at Chantilly on Sunday.
Ridden by Stephane Pasquier, the French colt started accelerating through the field on the home straight and hit the front with almost a furlong left.
In the last 300 metres, Patascoy, Louis D'Ord and Intellogent all challenged but Study of Man clung on to win by half a length.
"It's unbelievable, he's a great horse. I really rode a race that was not made for him," said Pasquier, who won the race for the first time at the age of 40.
Patascoy, ridden by Mickael Barzalona, was second edging Louis D'Or, under Antoine Hamelin, by a head.
The victory was the sixth in the French Derby for trainer Pascal Bary, who also saddled winners Celtic Arms (1994), Ragmar (1996), Dream Well (1998), Sulamani (2002) and Blue Canari (2004).
"Study Of Man is a very smart and alert horse," Bary said. "He understands everything, manages himself well and gives his all. He's a dream to train."
The horse is owned by the Niarchos family.
"It's fantastic," Electra Niarchos, grand-daughter of the tycoon Stravros Niarchos, said at the press conference. "It's the history of our family because Study Of Man is the grandson the champion Miesque, who carried our colours with distinction in the world of thoroughbred racing."
Sunday's race was over 2,100 meters. Bary admitted afterwards that Pasquier had said that Study of Man could go 2,400 meters, explaining this suggested "he could run the Prix de l'Arc de Triomphe" in October.
The best non-French finisher was Hunting Horn of Ireland, who was sixth.
Study of Man went off as second favourite at 4-1. Favourite Olmedo, at 3-1, finished 13th in the 16-horse field.
"Olmedo was very tense," said his trainer Jean-Claude Rouget. "He tugged a lot and completely ran out of breath."
Study of Man crossed the line just ahead of Patascoy and Louis d'Or to win the Prix du Jockey Club horse race at Chantilly.