The well-backed 4-7 favourite, unbeaten in her previous two starts for trainers John and Thady Gosden, never looked in any danger as she completed a five-and-a half-length victory over second-favourite Life of Dreams.
Dettori had her well-placed in the five-runner field throughout and, although she pulled hard in the early stages and was restrained by the jockey until two furlongs out, when he asked her to pick up she accelerated away from the field to quickly put the race to bed.
The daughter of Sea the Stars saw her odds for the Epsom showpiece tumble to a general 6-4 from 7-2 and John Gosden said he was impressed by her performance on the Knavesmire.
He said: “It’s interesting that Frankie said the ground was quite tiring after the little bit of rain they’ve had on it. A few of them were struggling four or five out.
“Frankie waited to go and she’s picked up well and looked like a mile and a half would be right up her alley. She couldn’t have done it any better really.
While the Clarehaven handler is confident in Emily Upjohn’s ability to handle the undulations of Epsom, he plans to give her a pre-race visit to the track for the Cazoo Derby Gallops Morning on May 23. He added: “She’s very well balanced, but there’s no reason we won’t get some sausage and bacon on the breakfast morning at Epsom. We can have a canter round the track there to see how she handles it.
“She’s a lovely filly and well balanced with a good stride and she’s learnt a lot today.”
Dettori added: “She was keen early on, but she’s in control and you want her like that.
“The ground is a lot deeper than you guys think. Everybody was struggling from four furlongs out and I kept her together and from two-and-a-half to the winning post, I didn’t see another horse.
“She won in good style by five and a half lengths - what more do you want?”
The Gosden-Dettori partnership completed a quick double as Samburu had to fight hard to maintain his unbeaten record in the Paddy Power ‘Here For The Craic’ Handicap.
The Kingman colt was the 4-5 favourite to follow Emily Upjohn’s success, but had to dig deep to see off Leyburn handler Karl Burke’s 50-1 outsider Snooze N You Lose by half a length.
There was a Yorkshire one-two in the other big race of the day - The 1895 Duke of York Clipper Logistics Stakes. The John Quinn-trained Highfield Princess (11-2) comfortably held off the challenge of Burke’s Spycatcher in the six-furlong event, with joint-favourite Minzaal in third.
The winner was always handy from stall one under Jason Hart and picked up nicely a couple of furlongs out to win impressively.
Malton’s Quinn said of the victor: “She was very impressive, just what I wanted to see.
“I think we’ll probably wait now until the six-furlong race at Ascot [Platinum Jubilee], that’s the obvious next race for her.”
Favourite-backers were rewarded in the first race of the season The Sky Bet Race to the Ebor Jorvik Stakes, as Gaassee stayed on well to win for Skipton-born trainer William Haggas and York’s leading jockey for last season, Tom Marquand. Forza Orta, trained at Hambleton by Kevin Ryan, was picked off in the final furlong by the winner, with the Queen’s Just Fine back in third.
Haggas said: “That’s a good start. He was lugging a bit to the left though, I don’t know why. He might have been a bit rusty, but he wasn’t as impressive as I’d hoped he’d be. Everyone loves winners at York, but I was born up here and I’m always proud to have winners at York.”
Michael Dods’ Dakota Gold returned to form with a photo-finish victory in the second race - the 6f Churchill Tyres Stakes.
It was the horse’s first win since 2020 but sixth on the Knavesmire making him joint winning-most horse at York with Tim Easterby’s Copper Knight. Malton-trained Makanah was second for trainer Julie Camacho and jockey Paul Mulrennan.
Dods also took third with Pendleton, while Asadjumeirah was fourth for Wartill’s Anthony Brittain and pilot Cam Hardie.
Irish raider Kihavah won the Conundrum HR Consulting Handicap for trainer Adrian Keatley and jockey Ryan Sexton and the final race of the day, the five furlong EBF Novice Stakes proved a clean sweep for Yorkshire, with Danny Tudhope winning on Kevin Ryan’s Thunder Moor, from Adrian Nicholls’ King’s Crown, with Grant Tuer’s Mersea.