The 13-2 shot showed an excellent turn of foot in the Classic trial, despite the mud. Ippon, ridden by Jean-Rene Dubosc, scored by two lengths from Silic, with the Peter Savill-owned Roi Gironde three lengths further back.
Diableneyev (fourth) and the front-running Middle Park Stakes winner, Hayil (last of five), who hated the ground, were the big disappointments.
Rouget said that Ippon may challenge for the 2,000 Guineas or tackle the French equivalent.
Andre Fabre's Uninhibited is still a 1,000 Guineas possible after failing to peg back Cortona (7-1) by a neck in the seven-furlong Prix Imprudence.
Walter Swinburn returned to the winner's enclosure for the first time in 18 months on a British racecourse when partnering Oh Hebe to victory at Leicester yesterday.
Swinburn, nearly killed in a fall at Sha Tin in February 1996, was slowly nursed back to fitness before gaining a tearful victory on Pilsudski at the Breeders' Cup at Woodbine in October 1996.
He then announced on April 21 last year that, owing to continuing weight problems, he would be taking a sabbatical from raceriding.
Adrian Maguire was yesterday given the go-ahead to return to race-riding tomorrow. The jump jockey has been out of action since he broke a collar- bone and suffered concussion in a fall at Cheltenham last month.