The well-backed J Wonder (4/1) got the better of Al Thakhira to land the Dubai Duty Free Stakes at Newbury.
Both the principals were given patient rides and Jimmy Fortune started to make his ground aboard the winner passing the two furlong marker.
Frankie Dettori and Al Thakhira (11/4 favourite) went forward at the same stage but couldn't quite match the winner's change of gear and went down by a head.
Frankel's half-sister Joyeuse (4/1) was another closer and took third, a further length-and-a-quarter adrift.
Winning trainer Brian Meehan said: "I'm really pleased as she has proved to be the filly we thought she was. It's not a shock, not by any means."We came here thinking she had to be in the first three on what we knew of her from last season.
"She was brave as she had to come through horses and Jimmy got off and said he felt she won very easily, she just pricked her ears when she hit the front and just needed one slap to keep her mind on the job.
"We thought she was special last year and she looked good today. She's in the French and English Guineas and I'll have to speak to the owner and Jimmy. We'll have a proper conversation, put it all together and decide."
Marco Botti said of the runner-up: "She has proved she retains her ability. I think seven furlongs might be her trip, but the French Guineas might give her a better chance at a mile. Ground is the key."
Lady Cecil said of Joyeuse: "She will definitely come on for the run and she's in the French and English Guineas. We'll see."
Sky Bet cut the winner to 12/1 from 50s for the QIPCO 1000 Guineas, spokesman Michael Shinners saying: "She was clearly expected to run well and you had to like the way J Wonder picked up. Both the front two look smart fillies at the very least."