Azamour made it third time lucky this season by winning the St James' Palace Stakes, the feature race on the opening day of Royal Ascot.
Michael Kinane and Azamour ride hard to the line
The colt was third in the English 2,000 Guineas in May and second in the Irish equivalent a fortnight later.
But Mick Kinane timed his run perfectly this time on the John Oxx-trained horse to edge out Diamond Green by a neck.
Refuse to Bend showed a good return to form under Frankie Dettori to win the Queen Anne Stakes.
The big disappointment in the St James's Palace Stakes was the favourite Haafhd, who could only finish fourth.
Richard Hills went for home on Haafhd with two furlongs to run, but it soon became clear that he would not be finding the turn of foot that has served him so well in the past.
He was soon swamped with Azamour, who had tracked Haafhd early on, finding the speed that mattered and he ran right to the line.
"In the Irish Guineas the feeling was that he was taken a little bit by surprise. We thought that he was a very useful horse and the rising ground here was what we were looking for," said winning owner the Aga Khan
"We will see how the horse is now. I think probably we will go somewhere in the 10-furlong distance, but he may even go further than that."
Kinane said: "I knew we hadn't got the best out of him in the two races so far but we were very happy with him coming into today."
Frankie Dettori and Refuse to Bend challenge Soviet Song
In the Queen Anne Stakes, last year's 2,000 Guineas winner Refuse To Bend claimed a dramatic victory.
Frankie Dettori brought the former Dermot Weld-trained colt to challenge Soviet Song in the final furlong and take the Group One prize for the second year running in
the Godolphin colours.
Soviet Song went on two furlongs out and although the favourite Six Perfections flattered briefly, it was Dettori's mount who put in a determined bid to land the spoils by a neck.
The Italian was delighted to see the horse back to his best.
He said: "I've been as worried as everyone else. He always worked good and we couldn't work out why he ran so badly in Dubai and the Lockinge.
"We have all dug deep and the team did a good job to get him back. He travelled really good today, even when he was boxed in he was going well."