Charlie Appleby's Kemari belied his inexperience to win the Group Two Queen's Vase at Royal Ascot on just his third career start.
William Buick, striking for the second time at this year's meeting, always had Kemari close to the pace just behind the leaders before challenging early in the straight and striking for home.
It proved the right move as the Dubawi gelding surged clear and then had enough in hand in the final furlong to comfortably resist the late challenge of Aidan O'Brien-trained favourite Wordsworth.
The 15-2 winner had a length and a half to spare at the line, as Wordsworth stayed on strongly after being unable to find a change of gear when it mattered most, and Stowell was another length and a quarter back in third.
Kemari, who made his debut when second at Newmarket little more than a month ago before winning a Yarmouth maiden, clearly relished the step up in trip as he provided Godolphin trainer Appleby with his first winner of this race.
Appleby said: "I must give the team at home a lot of credit for this. He's been a challenging horse at home during the course of the winter. He was gelded and had a hood on his first start, so all credit to them - they've done a great job.
"And William, he placed him highly after that win at Yarmouth. I have to say, I sat on the fence and thought he was a horse that was progressing, but whether he'd be progressing quick enough to step up into today's league - he's proven me wrong and William right.
"The horse is definitely going the right way."
He went on: "He'll hopefully make up into a Cup horse for next year. The last few years, three-year-olds in the Melbourne Cup have produced the goods, so whether he gets to that level, we'll see.
"We'll enjoy today and have the discussions with our principles and managers during the next few weeks and map the autumn out.
"He's a horse that's got a profile working in that direction (Melbourne), but whether he goes there, we'll enjoy today and have the nice discussions over the next few weeks."
Asked about the possibility of tackling super stayer Stradivarius in next month's Goodwood Cup with a hefty three-year-old allowance, Appleby replied: "We'll wait for a couple of days and see how the Gold Cup goes!
"He's a horse that's come to hand over the last eight weeks now, so whether that might be a step too soon for him, it's a nice discussion to have."