Berkshire Shadow sprouted wings in the closing stages to land the Coventry Stakes for Andrew Balding and Oisin Murphy.
Victorious over five furlongs on his debut at Newbury, despite fluffing the start, he looked sure to be suited by an extra furlong - and so it proved.
Murphy only had one behind him at halfway as they raced in two groups originally, with Wesley Ward's Kaufymaker and Joe Tuite's The Organiser putting the pace to the race.
As the groups converged there were plenty in with chances spread all across the track, but the champion jockey safely plotted a route up the stands rail.
Vintage Clarets hit the front on entering the final furlong with big outsider Eldrickjones and Ebro River all getting involved.
But it was the 11-1 chance Berkshire Shadow who quickened up best of all to maintain his unbeaten record by a length and a quarter from Eldrickjones, with Vintage Clarets third.
Owner Paul Spickett said: "It was special, just like at Newbury Oisin wasn't flustered and took his time.
"To see him come home like that was quite special.
"As the years go by I'm getting more careful about what I think as I used to think every winner was going to go on and win everything, but I did think he was special to do what he did at Newbury and we were hopeful coming here.
"I had my first Royal Ascot runners last year and we were all dressed up at home with nowhere to go, we were second in the Queen's Vase with Berkshire Rocco and that was amazing, but to have a winner is astounding.
"We backed him at 22-1 so we'll be able to buy some cheap champagne later."
Murphy said: "This is a special horse, he was bought inexpensively by Andrew and his mother and he's a star.
"That was an incredible performance on his second start. To look at, he's big and immature
"He's got a very good future - and look what he's just done at Royal Ascot.
"He's done incredibly well, what a massive result for Kingsclere!"
Danny Tudhope, rider of the Roger Fell-trained Eldrickjones, said: "On what he'd done at home we thought he might be up to this, but he's still a real baby and there's a lot more improvement in him."
Richard Fahey said of Vintage Clarets: "We do like him very much, he's run a blinder, and I wish he'd won but as he didn't he escapes a penalty for the Newbury Super Sprint."
His jockey Paul Hanagan added: "We would have been disappointed if he didn't run like he has, he's done everything we've asked him so far."