Vadeni produced a dominant display to provide trainer Jean-Claude Rouget with a fifth victory in the Qatar Prix du Jockey Club at Chantilly.
A field of 15 colts went to post for the French Classic, with a strong British contingent headed by Charlie Appleby's Poule d'Essai des Poulains winner Modern Games.
Also successful at the Breeders’ Cup last season, the son of Dubawi was quickly into his stride from his wide starting berth and soon navigated his way to the front in the hands of William Buick.
Modern Games remained in front halfway up the home straight but Vadeni, who returned an 8-1 industry shot and 68-10 on the PMU, loomed up ominously in the hands of a confident Christophe Soumillon and accelerated clear in hugely impressive style.
El Bodegon, a Group One winner in France last season for James Ferguson but disappointing on his seasonal reappearance in the Dante at York, bounced back to form with an excellent run to finish second, with Modern Games far from disgraced in third.
Andrew Balding’s Irish 2,000 Guineas third Imperial Fighter showed up well before fading, while Aidan O’Brien’s pair of Ivy League and The Acropolis were never able to get in a serious blow.
A delighted Rouget said of the winner: "I'm happy when a horse is flying like him today.
"I didn’t know before the race. I like him and thought he could run well. I thought he would stay the trip strongly but maybe didn’t have enough speed and would be better at a mile and a half.
"He had a very good draw and was always in a good position. After that, the acceleration was the same as when he won first time out last year in La Teste. He is a horse with a lot of class.
"He was not a smashing yearling, he was quite a poor yearling, but he improved a lot.
"I hope he will have a good summer and autumn."
Bookmakers introduced Vadeni into the Prix de l’Arc de Triomphe market at single-digit odds after his win, but Rouget hinted he is more likely to stay at a mile and a quarter like his 2016 winner Almanzor, who went on to land both the Irish Champion Stakes at Leopardstown and the Champion Stakes at Ascot.
When asked about the Arc, the trainer added: "I think we will do more the Almanzor programme, but it’s a bit early to be definitive.
"The Irish Champion is a smashing race and there’s Deauville if the ground is not too soft."
