Reckless Abandon swept to Group One glory in the Darley Prix Morny at Deauville.
Clive Cox's youngster was quickly away, enabling Gerald Mosse to grab the stands-side rail and make the running.
The Norfolk Stakes and Prix Robert Papin winner was given an easy lead in front and had plenty left in the tank in the closing stages as he stepped up to six furlongs for the first time.
The Aidan O'Brien-trained pair of George Vancouver and Parliament Square finished strongly, but had to settle for second and third respectively.
Cox said: "We're all over the moon. He's done it really well and I couldn't be happier. It's been a wonderful week and weekend, what with winning the Hungerford with Lethal Force on Saturday - it's what you dream about.
"It's our second Group One. Gilt Edge Girl won the Abbaye for us, but to have a two-year-old Group One winner is something special.
"I would think the Middle Park (Newmarket, 13 October) would be the logical next step.
"I was very impressed with his whole performance."