Tony Vasil had already declared Prince Harada potentially one of the best horses he has trained.

But a stunning last-to-first win in the colt's city debut at Moonee Valley on Saturday only helped to justify that opinion.

Prince Harada, a son of Vasil's former star galloper Haradasun, was sent out an odds-on favourite in the Alternate Railway Handicap (1200m) and had to be saved for one run from last after missing the start.

Despite the leader Boer ($5) kicking strongly, Prince Harada ($1.85) ran down his rival to win by a length with 1-3/4 lengths to Countersnip ($6) third.

Vasil said the colt had obvious talent and would now be given a let-up to be aimed at the Group One Caulfield Guineas (1600m) in the spring.

Having trained multiple Group One winners Elvstroem and Haradasun, Vasil, who still rides trackwork, is well placed to judge the potential of a horse.

"I've been riding horses for 35 years and I've had some good ones too," Vasil said.

"He's just got that wow factor.

"He's got a massive action and is still green as grass."

Jockey Steven Arnold said he had no option but to ride the colt quietly after he was slowly away.

He also believes he can be a spring horse and get to 1600m.

"He's got a turn of foot, a good action and is improving," Arnold said.