The Ger Lyons-trained colt, owned by Khalid Abdullah, forged clear in the final half-furlong to comfortably land the spoils, after all five runners were in with a chance at the business end.
The quintet were spread right across the track a quarter of a mile from home with Siskin the nearest to the stands side.
When asked for an effort by Colin Keane, the 11-8 favourite found plenty to win going away by two and a half lengths from King Neptune.
Lyons said: “He’s very straightforward and has been from day one. I’d love to tell you how difficult it is to train him and how brilliant I am, but it’s push button stuff when you have horses like this. He has a fantastic temperament.
“As I’ve been saying for years, training horses is not rocket science – it’s about getting the horses and if you don’t have the horses you can’t train the winners.”
He added: “Colin said you can drop him back, you can step him up, you can do what you like on him.”
The First Defence colt was given an 8-1 quote for the Coventry Stakes at Royal Ascot by RaceBets, but Lyons has his sights set on targets closer to home.
He said: “Our initial plan is to stay here for the Railway Stakes, but I’ll have to talk it over with the owners. The important thing with him is to try to aim at a Group One and not leave it in Ascot.
“My plan would be to stay at home and hopefully have a Phoenix horse.”
The O’Brien-trained colt had just failed in a handicap at Cork last time out, when his chance was hampered in being short of room at a crucial stage.
But Ryan Moore had got to work on the son of Galileo, who was held up in the rear through the early stages, and the 10-11 favourite responded to pick up Buckhurst as the post loomed, scoring by half a length.
O’Brien said: “He’s a lovely big horse and is still a big baby. He quickened well and came home well. He’s a nice mover and appreciates good ground.
“We won’t rush him. We could pick a race for him in Ascot, but will go gentle with him.”