Goldream clinched victory after a thrilling climax to the King's Stand Stakes at Royal Ascot.
Robert Cowell's sprinter landed the Palace House Stakes at Newmarket on his penultimate start before failing to fire in Haydock's Temple Stakes and was sent off at 20-1.
Martin Harley settled his mount on the heels of the leaders before asking Goldream to go about his business entering the last of the five furlongs and he galloped all the way to the line to provide Cowell with a second victory in the Group One contest following the success of Prohibit in 2011.
Veteran sprinter Medicean Man looked as though he might cause a 50-1 upset as the line approached, but Goldream got up to beat him by a short head.
Muthmir was just a neck away in third, with Pearl Secret fourth.
Popular Irish sprinter Sole Power was the 5-2 favourite to become the first horse to win the King's Stand three times, but having been held up, his trademark late burst was not as potent as it has been in the past and he passed the post in fifth.
Harley said: "He travelled real good. I crossed over a little leaving the stalls as all the fancied horse were drawn high.
"He picked up well just beyond the furlong (pole) and by God he's game.
"I was lucky because I changed my hands with a furlong to go and nearly dropped my stick.
"Fair play to Robert, he said going out that he was in good form but the ground is obviously a big thing with him, he travelled well the last day at Haydock but went out very quick.
"My first winner here was for Mick Channon and that was great as he supported me when I came over (from Ireland), but this is great as Group Ones are hard to get."
Cowell said: "He's been brilliant. I must say I didn't think he'd win a race like this, but I thought he was getting to that sort of level.
"It was a brilliant ride, I'm so pleased for the owners who have stuck with this horse, we decided to raise the bar and they told me to do what I want.
"I'm a bit overwhelmed. Tom Morley, who is involved in this horse with his mother, was involved with Prohibit."