Drochaid just held off the late lunge of Emenem to win the Investec Private Banking Handicap.
Andrew Balding's three-year-old has been in consistent form and was following up a win at Chelmsford.
In a typically messy Epsom handicap, Franny Norton dived for the rail on Emenem, causing Aaron Jones on Hajaj to snatch up as Emenem made strong late progress.
A confident-looking Oisin Murphy may have got a fright as eventually Emenem closed to within a neck of Drochaid (11-2), with Desert Skyline another length back in third.
Murphy said: "He'd not as much experience as the others, but he travelled well and won easily.
"I think he is a horse who could take another step up when he goes up in trip."
Balding said: "It was a really good effort, we'll have to have a think now. You'd hope he'd go on and improve.
"To be honest, we were confident he would see the trip out well. Oisin had him in the right place. I am delighted and he is an improving horse.
"He tends to do that (be a bit keen), but he is a tough horse that always keeps finding. He is going in the right direction and there might be more to come.
"We are working through the grades and we might have a look at a valuable mile-and-a-quarter handicap at the July meeting at Newmarket."
Norton was found guilty of careless riding aboard Emenem and suspended for seven days.