Dr Marwan Koukash had already achieved his major racing ambition by winning the StanJames.com Chester Cup five years ago, but he celebrated his second victory in the race with equal relish.
The locally based owner has a long-running love-affair with the May meeting, instructing his numerous trainers to prime his horses for it, and Richard Fahey had Address Unknown (12-1) spot-on for his first start for the yard.
Koukash's retained jockey Jamie Spencer was intending to partner the withdrawn Montaser, and picked the ex-Ian Williams six-year-old over three others in the valuable staying handicap.
Top-class hurdler and 7-2 joint-favourite Countrywide Flame had been right at the front throughout and looked to have made the decisive move turning for home, but his stride began to shorten and Unknown pulled past.
He eventually held on by half a length from the closing Ingleby Spirit to complete a famous one-two for Fahey's Yorkshire stable.
Koukash said: "I'm absolutely delighted. When we lost Montaser, I thought that was my luck gone, but Jamie gave this horse a fantastic ride.
"Richard has done extremely well with the horse over the past couple of months.
"I'm over the moon. I've been in racing five or six years and the only thing I wanted to do was win the (Chester) Cup again.
"To be honest, this means more to me than if I were to win the Ascot Gold Cup.
"This and the Melbourne Cup are the ones I want to win - I have a few contenders and perhaps this horse will be one."
Fahey said: "We haven't had him that long and I never checked that he normally wears blinkers and a tongue-tie.
"To finish first and second in a race like this is fantastic for everybody. It looked a right race on paper.
"Marwan said when he ( Unknown) came to me he'd win the Chester Cup.
"All I did was exercise him and bring him here - and forget the blinkers and the tongue-tie!"
Hughie Morrison suggested Banoffee (9-1) would be supplemented for next month's Investec Oaks after making a striking impression in the Weatherby's Bank Cheshire Oaks.
It is not uncommon for the Listed event to provide Epsom winners - Light Shift warmed up here in 2007 - and it was the manner of her performance more than anything which could persuade her owners to spend the £30,000 to confirm entry.
The daughter of Hurricane Run scored on her recent debut at Newbury and ripped through most of the field in just over a furlong, despite expending valuable energy by pulling hard through the early stages.
Morrison said: "I think we have to consider supplementing her for the Oaks.
"I was embarrassed I didn't put her in the race back in March, but she wasn't showing me anything like this.
"She was actually coughing at the beginning of March, so it would have been a brave shout to spend the money, but I think we will go home and discuss it.
If she is in good form she will probably go there.
"She has just surprised me, but she is obviously good."
Jockey Kieren Fallon said: "You would have to think she was an Oaks filly, the way she quickened.
"She has obviously improved a lot since Newbury."
Local trainer Tom Dascombe looked relieved as Quatuor (9-2 joint-favourite) sprinted well away in the Manor House Stables Lily Agnes Stakes, a race his yard sponsors.
"That takes the pressure off," said Dascombe, who is based at the stable co-owned by footballer Michael Owen.
"The owners are all local and this was part of the reason she was bought. It's a bonus where we go from here. I think she might run in the Listed race at York next week."
There was a fleeting moment of interest when Alex Ferguson's Butterfly McQueen horse made a spirited effort in the Boodles Diamond Maiden Stakes on the day the Manchester United manager announced his imminent retirement but she was picked off by Space Ship (5-1).
"He was the most experienced horse and that counts for a lot here," said winning trainer John Gosden.
Jockey John Egan earlier secured his first winner in Britain since September 2010 when Forest Edge (12-1) claimed the Stellar Group Handicap.
Egan arrived late on the scene aboard the David Evans-trained four-year-old, who held Captain Dunne by two and a quarter lengths.
Evans said: "He had a good draw and I knew once he got out in front they wouldn't catch him.
"It's a nice prize to win and I seem to have got John Egan out of retirement.
"No-one rides better than him round here."