The Roger Varian-trained four-year-old put up a career-best performance to ward off all challengers under an inspired ride by Andrea Atzeni.
Ajman Princess plugged on gamely to hold Siyoushake and Left Hand.
Smart Call, trained by Sir Michael Stoute, and John Gosden's So Mi Dar were also not far away, though the latter was slightly disappointing.
The stewards held an inquiry into possible interference linked with Ajman Princess, but Varian's inmate was eventually announced the winner.
Sky Bet cut the winner to 14/1 from 25s for the Qipco Fillies & Mares at Ascot on Champions Day.
Varian said: "That was very satisfying. "I have to thank Sheikh Mohamed Obaid (owner) to start with as it was his idea to change the tactics.
"She liked the ground. She was a very impressive Listed winner at Goodwood in May but she ran well in defeat in Group Threes and Group Twos since and this was a very attractive Group One for four-year-olds and upwards, falling where it does.
"It was a nice spot and the ground dried out in our favour.
"She's been a bit unlucky on heavier ground, which might explain her performance, so this drying out ground suited much better.
"She's a good-striding filly and Andrea gave her a very, very good ride.
"She's a Group One winner now so if she doesn't do anything else it's not the end of the world and we'll celebrate this.
"She's in the Prix de l'Opera and in the Breeders' Cup at Del Mar so we'll see what happens."
Morrison strikes in Kergorlay again
Marmelo gave trainer Hughie Morrison back-to-back victories in the Darley Prix Kergorlay when making virtually all the running in the Group Two at Deauville.
The four-year-old settled nicely in front for Christophe Soumillon and smoothly saw out the 15-furlong stamina test.
Desert Skyline, trained by David Elsworth, made late progress to snatch second place.
Holdthasigreen was third with last year's winner, Nearly Caught, fourth past the post for the Morrison team.
Sky Bet went 14/1 from 25s about the winner for the Qipco Long Distance Cup.
