Aidan and Joseph O’Brien failed in their bid to complete a Derby double as Imperial Monarch finished a luckless eighth behind shock Prix du Jockey Club winner Saonois.
The father-son combination headed to France following a fantastic day at Epsom, with 2000 Guineas hero Camelot completing a Classic double in the English Derby, sparking dreams of the Triple Crown.
The unbeaten Imperial Monarch appeared a leading candidate for the French equivalent at Chantilly following his victory in the Sandown Classic Trial last month, but found himself last turning for home after being shuffled back in a rough race.
Switched wide to challenge in the straight by O’Brien junior, the three-year-old found top gear and was flying at the finish, but was unable to reel in the leading group.
The jockey said: “It was a very rough race.”
The honours went to Saonois, trained by J-P Gauvin and ridden by Antoine Hamelin.
Hamelin, who only lost his claim this year, is apprenticed to Alain de Royer-Dupre.
The jockey said: “There was no real pressure as we didn’t have a great draw and my trainer just said I should ride him the best I could.
“I have never ridden in a Group One race before and winning the Prix du Jockey Club is a dream come true. I was told to enjoy myself and I did.”
Godolphin’s Saint Baudolino claimed the runner-up spot in a bunch finish for the places.
Racing manager Simon Crisford said: “We are happy with that, it was a big effort. It was just a bit of a messy race, but we are delighted with the way he ran.”
