The son of Sea The Stars was beaten on his first two outings but hinted at his ability when winning a novice race last time out by 10 lengths.
He was taking a big step up in class for this Group Three but proved well up to it as he took up the running on the bridle more than a furlong out for Jim Crowley.
Watch a full replay of how the son of Sea The Stars shone at Newmarket on Thursday
Ryan Moore set out to make all on the favourite Dawn Rising, only to be taken on first by Sound Of Cannons and then Miss Yoda before – having seen them off – he was brushed aside by Al Aasy (3-1).
On hitting the front Al Aasy began to idle as Dawn Rising stuck to his task well, but he was beaten by a length and three-quarters.
The winner was introduced into the betting for the St Leger at 8-1 by Betfair.
Crowley said: “I was impressed. We’ve always held him in high regard, but I was very disappointed with his first start on the Rowley Mile course – he just didn’t run a race.
“Obviously he backed up quickly and won, and then he’s taken another step forward today and won well.
“He definitely stays but he’s not a slow horse, he’s always shown pace. If they wanted to go for the Leger, I’m pretty sure he’d stay.
“I just think he’s improving all the time. He’s a big horse and hopefully he’ll keep on improving.”
Haggas’ wife and assistant Maureen, said: “William has always loved him. He is a beautiful horse. He is bred to be a good horse.
“He ran really well first time last year, and we were really disappointed when he went to Newmarket first time this year and ran like he did. I don’t know why he did – maybe he was just a bit rusty.
“He did what he did last time, beating probably not a lot, but he is going in the right direction -which is great. He is improving and learning. When he won last time, this is where William wanted to come.
“He was our Derby horse -and when William showed him to Sheikh Hamdan (owner) as a yearling he said ‘this is the Derby horse’. He just wasn’t experienced enough to go for something like that.
“Hopefully he will be here next year, and he will be a stronger horse again. I think he will be better on faster ground, because most Sea The Stars want faster ground. He is not a slow horse, so I think a strong-run mile and a half would be ideal for him.”
Richard Hills, racing manager for the owner, said: “It was only a novice he won last time, but he won it well .
“His work has always been really good. You have to look at him realistically as a Leger horse. I’d say William would be looking at York (for the Voltigeur), then seeing where he is.”
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