Carlton House, owned by the Queen, is the new favourite for the Derby after winning the Dante Stakes at York for trainer Sir Michael Stoute.
The 11-4 shot came through the six-runner field with a late burst of speed, with 5-4 favourite Seville having to settle for second place.
The Queen has never won the Derby, but Carlton House could be the one that breaks the royal duck after jockey Ryan Moore brought the colt home first.
Pisco Sour (40-1) took third place.
William Hill gave Carlton House a price of 5-2 for the Epsom Classic in June, but other layers offered only 2-1 or shorter.
John Warren, the Queen's racing manager, said: "That was better than I expected as I was slightly pessimistic.
"I loved the way he went through the gap as it shows he'd have no trouble with a course like Epsom where you might get trouble.
"I talked to Her Majesty through the race and she was concerned about the lack of pace but when he went through the gap she let out a yelp!
"I think the fact they went no gallop could benefit him in the long run as he has only raced for three furlongs.
"The Queen will be at Epsom and this will mean a lot to her. It is fantastic for racing and if she can help the industry, all the better."
The early leader was Pisco Sour, but there was no early pace and both Carlton House and Henry Cecil's World Domination took a pull in the first furlong or so.
Jimmy Fortune, on Pisco Sour, took the runners across to the stands side in the straight, at which stage the race began in earnest.
Christophe Soumillon got the rail position on the Aidan O'Brien-trained Seville, with Carlton House just in behind as Moore waited for a gap.
Once that came, it was a straight fight between the first and second, and Carlton House pulled a length and a half clear as the winning post came.
Stoute said: "I'm very pleased with him. We thought it could be a messy race, and it certainly turned out to be that.
"He learned a bit and I was delighted. He went through a tight opening and let's hope he can progress a bit more from that.
"In the early part of the race he was just a little keen, which is uncharacteristic.
"I would be surprised if the trip was a problem in the Derby."
O'Brien was satisfied enough with the performance of the runner-up Seville.
He said: "The winner picked up better than we did. We can't complain, and the likelihood is he'll go to Epsom."
World Domination, who finished fourth, may now swerve the Derby.
Teddy Grimthorpe, racing manager for owner Prince Khalid Abdulla, said: "We are happy enough, but he's still a big baby.
"At this stage I'd say Epsom is unlikely - he might go to Ascot."
However Pisco Sour's trainer Hughie Morrison said: "We obviously have to look at the Derby now."