Andrew Balding's Youth Spirit emerged as a Derby contender in causing an upset with a clear-cut victory in the Chester Vase.

Blue Riband Trial winner Wirko was favourite to cement his Epsom claims for Charlie Appleby, while Law Of The Sea – already a dual winner this year – also carried the Godolphin colours for John and Thady Gosden.

Aidan O’Brien, who had saddled seven of the last nine winners of the Group Three contest, was represented by Craven Stakes sixth Sandhurst – but it was 15-2 shot Youth Spirit who stole the show.

Wirko cut out much of the running under William Buick, but was a spent force before the home turn, at which stage Fancy Man looked the most likely winner when sweeping to the front.

However, while his effort was ultimately short lived, Youth Spirit – fourth in the Feilden Stakes at Newmarket three weeks ago – finished with gusto under Tom Marquand to prevail by a length and three-quarters.

Sandhurst was one of the first off the bridle, but boxed on well to beat Fancy Man to the runner-up spot.

Bookmakers went 25-1 about Youth Spirit’s chance in the premier Classic, and Marquand – sporting the colours of last year’s Derby runner-up Khalifa Sat – said: "To be honest he was a bit behind the bridle, this was my first time riding him and it looked like he did that over nine furlongs at Newmarket.

"That must just be his run style because when I sat into him and gave him a proper squeeze coming to the three he was all there for me.

"The one question he had to answer was the trip, but you’d have to say he hit the line extremely well. It was a muddly race, but he’ll stay in an honest-run race as well.

"Chester is a funny old place and if you swing out your race can be over, but I followed William and I knew he’d take me into the guts of the race. He was really tough, stuck his head out and was there for me."

Balding was represented by his wife, Anna Lisa, who said: "Andrew has always thought a lot of him and today has shown what we wanted to find out.

"I’m sure the owner will be looking forward to a runner in the Derby so I’d be amazed if he didn’t show up at Epsom.

"Somebody made me aware the other day that it is 50 years since Mill Reef won the Derby for Kingsclere, which is fantastic, but it will be a little bit quieter this year.

"When Tom got on him he said 'a Camelot round here on soft ground, he’ll love it’ and he was right. He was a massive price, I couldn’t believe it.

"Andrew’s record in the Derby isn’t great, but he was second and fourth last year."

Dubai Fountain (13-8F) booked her Epsom ticket as she made a successful reappearance in the Weatherbys ePassport Cheshire Oaks.

Mark Johnston's filly was the clear standard-setter on juvenile form, which included a fourth-placed finish on her most recent appearance in the Group One Fillies’ Mile at Newmarket in October.

The daughter of Teofilo was ridden by Chester specialist Franny Norton, who after tracking the pacesetting Quenelle D’Or for much of the contest, committed for home before the home turn.

That decision from the veteran Liverpudlian may well have proved crucial, as the previously unbeaten Zeyaadah was briefly caught in a pocket before the gap came early in the home straight, by which time Dubai Fountain was in full flight.

Zeyaadah made inroads late on, but the Johnston runner had enough in the tank to keep her at bay by a length.

Johnston said: "Franny said it was very stop-start and he was happy to get a lead, but the pace was on and off which didn’t really suit.

"He was having to wake her up and then steady her again, so he could never get her into a nice rhythm – he felt it wasn’t her best performance, but it was good enough for me, I was happy with that.

"It will be straight to Epsom now, we were saying throughout last year we thought she was an Oaks filly rather than a Guineas filly.

"She obviously failed to win a Group race last year, but she ran some great races. We’ve been thinking about the Oaks for a long time.

"She was beaten just a length by the Guineas winner (Mother Earth) over a mile last year, when we always felt she’d be better over further.

"I don’t think the key to her chance was going up in trip, she’s good enough, otherwise you’d be saying that about every horse who ran in a trial. She’s been running at that level (Group One) there’s no reason to think she’s not good enough.

"We’ll just have to hope there’s not one better!"