Al Husn pounced late as she wore down the dual Group One-winner Nashwa to cause a minor surprise in the JenningsBet In Shiremoor Hoppings Fillies' Stakes at Newcastle.
Nashwa won the Prix de Diane and Nassau Stakes in a glittering three-year-old season, while she also ran well in the Oaks, the Prix de l'Opera and at the Breeders' Cup.
She was sent off the 8/11 favourite to get back to winning ways under Hollie Doyle, who tried to dictate matters from the front.
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John and Thady Gosden's Nashwa raced keenly throughout but when Doyle asked the Frankel filly to put the race to bed, she immediately took a couple of lengths out of the field.
However, she did not make life easy for Doyle and began to hang to her left, and all the while Jim Crowley was coming with a strong run on the Roger Varian-trained Al Husn.
Al Husn (3/1) herself was a Listed winner last time out and had only lost one of her previous five races so is clearly on the upgrade and she continued her progression.
Deep inside the final furlong as Nashwa began to tire, Al Husn was hitting top gear and won by half a length.
Crowley told Sky Sports Racing: "She's clearly thriving, she looked so well in herself tonight.
"We managed to get a really nice position and it was a bit of a rush when we turned for home but she picked up nicely and hit the line well.
"She's improving all the time and from that run we can crack on and aim a little bit higher. She's a little terrier."
Asked if the winner had earned a shot at next month's Group One Nassau Stakes at Goodwood, Crowley said: "I think so. You've got nothing to lose in a race like that and everything to gain."
Meanwhile, it is back to the drawing board for Nashwa's connections.
Teddy Grimthorpe, racing manager to owner Imad Alsagar, told Sky Sports Racing: "We expected a really good run from her. She obviously needed the run in France but has been straightforward in her work at home since so that gave us every confidence.
"She seemed to travel well and Hollie was very happy until the very last bit.
"We have some thinking to do and I'll speak to John [Gosden, trainer] and Imad to see what the best plan might be.
"Ideally we'd still think about the Nassau but we'll have to give it all some consideration."