With four Group Ones now in the locker, including the Irish 2000 Guineas, Mastercraftsman is well up on the former hero at this early stage of his career but will need to shine in the all-aged heats later in the summer.

Johnny Murtagh found himself taking over from his pacemaker Set Sail around the home turn but was soon joined by both English 2000 Guineas runner-up Delegator and Lord Shanakill.

Delegator (4-1) even snatched an advantage of about a head inside the final furlong, but 5-6 favourite Mastercraftsman was not interested in being second best and pulled back to finish a neck in front at the line.

"He's just one of those great horses," said O'Brien. "He's becoming very like a Giant's Causeway, the sort of horse that doesn't mind a mile or a mile and a quarter.

"He's an amazing horse with speed, stamina, and all ground comes alike to him.

"It was a great performance from the horse and a marvellous performance from Johnny.

"He's a big, straightforward horse and is very uncomplicated - he just jumps out and you let him roll.

"Johnny said he's very idle when he hits the front but watching the race, I knew that Johnny didn't think he was beat."

O'Brien said he believed Mastercraftsman had improved since the Curragh but revealed: "It is the people who are dealing with them who tell you 99% of what you know. My job is to listen."

Murtagh added: "He gave 110%, he's brave, courageous, he's like all the great horses I ride for Ballydoyle - they never know when they're beaten. He's just like Henrythenavigator and Duke Of Marmalade last year.

"I think he didn't handle the hill in the Guineas at Newmarket and I was confident he could turn the tables. A lot was made of him winning because of the soft ground in Ireland but it was perfect today and I think a good horse goes on any ground.

"He's won a Guineas and a St James's Palace over a mile, he's not short of speed. I think he's a true champion and he deserves a lot of credit."

For Delegator and trainer Brian Meehan it was redemption after his disappointment on soft ground in the Irish 2000.

Meehan said: "Fifty yards out it looked like he had his head in front but the other horse came back strongly.

"It was a hell of a run and it pours ice on all the people who knocked him in Ireland.

"I'll have to take him home and sleep on it before deciding where he goes next.

"Royal Ascot always brings out the emotions but they were wrong and we were right."

Lord Shanakill was a further length and a half back and handler Karl Burke added: "He's never let me down but I felt I let him down by running him in the 2000 Guineas (when unplaced).

"Today he's proved he gets the mile and that he's trained on. He'll have an entry in the Prix Jean Prat at Chantilly (July 5)."