William Buick and John Gosden teamed up to deny favourite Adelaide in the King Edward VII Stakes with Eagle Top (12/1).
Just as in the prevous race, it was a last-to-first move that paid off for the winner as Buick held Eagle Top up well off the pace set by Odeon in the early stages of the Group Two contest.
Turning for home, Lingfield Derby Trial winner Snow Sky looked to be going ominously well on the heels of the pacesetter, but he was unable to quicken and it was Adelaide and Bunker who then came to challenge.
However all the while William Buick had been easing his way into contention along the outside of the field and after initially taking a pull two furlongs out, he struck for home at the furlong-pole and soon went clear to score from Adelaide.
Scotland ran on strongly for third, having been under pressure from a fairly early stage of the contest.
"I didn't realise he was this good," Buick said. "He swatted them off in a matter of strides. It was only his third run and everything is open to him.
"He baffled me a bit today. I just didn't realise he had that kind of speed.
"He came here, he didn't turn a hair and was very relaxed. He's got all the attributes of a top, top racehorse.
"This horse... you'll be hearing a lot more from him."
It was a first Royal Ascot winner for owner-breeder Lady Bamford, who said: "I feel weak at the knees. I don't know what he (Eagle Top) feels like!
"He has a beautiful trainer, a trainer in form, and he was a very unexposed horse, but my goodness he showed his form today, didn't he?"
Gosden, already on the mark on Tuesday with Kingman and 24 hours later with The Fugue, added: "He won his maiden well, then we had that dreadful day at Leicester when he was beaten in a handicap.
"This is a dream for owner-breeders. I can't emphasise enough the agonies you go through.
"This is a lovely horse and he quickened really well."
Gosden won the King Edward in 2011 with Nathaniel, who went straight to the King George VI And Queen Elizabeth Stakes, where he beat Derby hero Workforce.
Asked if the midsummer showpiece could be an option for Eagle Top, Gosden said: "We've supplemented a King Edward winner before for the King George in Nathaniel, so I'd never be frightened.
"If this horse was right he might be considered, but that is not the plan at this stage. He is a tender three-year-old and has just had three runs.
"I love the St Leger, but he is not a horse for that race and hopefully I have two, in the Derby third (Romsdal) and Forever Now, who won a maiden at Doncaster on Sunday.
"He wasn't entered for the Grand Prix de Paris as it closed in February and he hadn't even run then."One horse who could head for the St Leger now is third-placed Scotland, his trainer Andrew Balding commenting: "That was a smashing run. He was staying on well. We probably should have gone for the Queen's Vase but he hadn't given the impression he wanted further before today. He could go for a St Leger trial now."
"I'm delighted with his run and the winner is obviously improving," said Adelaide's trainer Aidan O'Brien. "I'm not sure where ours will go now but he likes fast ground."