Mustashry wore down long-time leader Forest Ranger to take the Group Three Betfred Mobile Strensall Stakes.
Sir Michael Stoute's four-year-old backed up a win at Chelmsford 11 days earlier with a hard-fought success in the colours of Sheikh Hamdan Al Maktoum.
Forest Ranger made a bold bid to make all the running over the nine furlongs and had most of the field off the bridle when he increased the tempo from two furlongs out.
But the 5-2 favourite got on top close home to gain the verdict by three-quarters of a length. Sovereign Debt was third.
Winning jockey Jim Crowley said: "He did very well to win at Chelmsford the other day and he's not got too many miles on the clock.
"I always felt I had plenty of horse underneath me. He's a nice horse."
Sheikh Hamdan's racing manager Angus Gold said: "We've always thought highly of him and he's finally getting to show his potential.
"He kept on getting held up by a splint, but he's a late-maturing type.
"Sir Michael always thought he'd stay 10 furlongs, I wasn't sure looking at his pedigree, but it looks like it would be well within his compass.
"We'll consider all the options for him now and hopefully he'll be around another year."
When asked if a supplementary entry for the Champion Stakes would be considered, Gold said: "I'd have to talk to Sir Michael, he might want to take it softly with him this year and he may think that would be too much of a leap."