Young Rascal gave James Doyle and William Haggas victory in the 100th running of the Chester Vase on the opening day of the May meeting.
On his third career start, the 10-3 shot showed nice speed in the Derby trial to outpace Dee Ex Bee (12-1).
The horse is owned by Bernard Kantor, the managing director of Investec who sponsor the Epsom Classic on 2 June.
Earlier, jockey Ryan Moore and trainer Aidan O’Brien combined as Magic Wand (3-1 fav) won the Cheshire Oaks.
Young Rascal, who won last time out at Newbury, got caught between runners as they turned for home at the Roodee with plenty of horses still in contention.
However, Doyle guided his mount through and past the O’Brien duo Hunting Horn and Flag of Honour in a matter of strides.
Dee Ex Bee, trained by Mark Johnson and ridden by Franny Norton, was the only one able to respond and they pulled away from their rivals but it was Young Rascal who proved the stronger to win by half a length.
Haggas, who won the Derby with Shaamit in 1996, said: “The Derby favourite (Saxon Warrior) looks pretty impressive, but you should never be scared of one horse and we’re entitled to run.”
Magic Wand had led from start to finish in the Cheshire Oaks with Moore taking advantage of the inside draw and winning by three and a half lengths.
Stablemate Forever Together was second with another Irish raider, Princess Yaiza, third for Gavin Cromwell.
“She was very smooth. Obviously she had the one stall and she got away well,” said Moore.
“She will carry on improving. This was a big step up from her last run and these fillies at this time of year should be improving and I’m sure she will.”
Analysis – ‘Lots to like here’
BBC racing correspondent Cornelius Lysaght:
Just the sort of result that the Derby needed. Although Young Rascal’s owner is a very well-off financier and William Haggas a leading trainer, the fact is that the colt doesn’t represent one of flat racing’s ‘superpowers’ who’re increasingly dominant and whose achievements, while laudable, are not likely to catch the public imagination.
As for the winning performance, there was lots to like here: racing for only the third time, he still showed signs of inexperience, and was impeded twice at potentially crucial times late on before storming home from Dee Ex Bee -but do remember last year’s runner-up then won at Epsom.