Outsider Barefoot Lady (14-1) won the Nell Gwyn Stakes at Newmarket to complete a notable double for jockey Paul Hanagan and trainer Richard Fahey.
The duo had carried off the Tattersalls Millions Sprint with Sir Reginald.
And in the day's feature, Barefoot Lady's dash for the line saw her beat 9-4 favourite Sing Softly by a neck.
The European Free Handicap was won by the Sir Alex Ferguson-owned Pausanias while Poquelin returned to winning ways for Paul Nicholls at Cheltenham.
Barefoot Lady delivered her challenge fast and late having appeared to have her work cut out in this Group Three affair, and she still had much to do passing the furlong marker.
The Aidan O'Brien-trained Sing Softly appeared to have made a winning manoeuvre when sweeping to the lead in the closing stages under Ryan Moore, but she hung to her right.
And Barefoot Lady, given an assured ride by champion jockey Hanagan, caught her on the line with Maqaasid (4-1) third.
The Nell Gwyn Stakes is traditionally a trial for the first Classic of the season, the 1,000 Guineas on 1 May.
Barefoot Lady does not hold an entry for that race but Fahey said afterwards a supplement might be paid by owner Norman Steel to get the filly in.
Fahey said: "She's only slight but Paul said they don't come much tougher. I've got to have a proper chat with the owner about supplementing her.
"There was a question mark today about the trip but on that display she should stay a mile. I've had a runner in the Oaks before but never in the Guineas. We're not used to this!"
John Gosden said of Maqaasid, just three-quarters of a length further away in third: "She was giving away 3lb to the rest of them so, on the weights, she's the best filly in the race.
"If the owners want to go for the Guineas, there's no reason not to."
Racing continues on Thursday at Newmarket with the 2,000 Guineas trial, the Craven Stakes, off at 1610 BST.