Miss France bounced back to her best to provide master trainer Andre Fabre with his first Qipco 1,000 Guineas at Newmarket.
A desperately disappointing sixth on her return to action in the Prix Imprudence at Maisons-Laffitte, she was even removed from the betting for the Classic by some bookmakers at that point.
However, confidence returned in recent days and Maxime Guyon sat just off the pace before kicking on before the dip.
She just held off Olly Stevens' Lightning Thunder - the filly she beat in the Oh So Sharp Stakes at Newmarket in September - by a neck.
The Saeed bin Suroor-trained Ihtimal was third.
Richard Hannon's Manderley defied her huge odds, and having set the pace the 100-1 chance was still in front with a furlong to run before finishing fourth.
Euro Charline turned the tables on her Nell Gwyn conqueror Sandiva and ran a big race just out of the frame
There was huge market confidence behind Aidan O'Brien's Tapestry who was sent off favourite but was virtually pulled up, while Lucky Kristale was far too keen for her own good.
Clive Brittain's Rizeena was not totally disgraced, coming home just behind the leaders.
Fabre, completing a full house of British Classic successes, said: "This means a lot, I trained the dam of the filly and I could not be more delighted.
"It was not the way I wanted her ridden, but it worked.
"She will get further, that is not a problem.
"She'll go for the Prix de Diane next, her dam won over a mile and a half."
Stevens said of the runner-up: "We're thrilled, this is childhood dream stuff, to be here with a horse of this quality.
"She's in the Irish Guineas, but she'd have to really bounce out of this to go on the ferry.
"She goes well fresh so it's more than likely that we'll save her for the Coronation Stakes at Ascot."