John Gosden and William Buick combined to spring a 33-1 surprise in the Betfair Supports The Animal Health Trust Fred Archer Stakes with Polygon.
Their representative had shown very little in two runs this season but would not allow hot favourite Dandino the chance to take control and held him by half a length.
"She didn't like the ground first time and was in another world last time so I popped the blinkers on at home," Gosden said.
"She's Group Three-placed so you've got to look at other staying Group races and you wouldn't be afraid of putting her in the Yorkshire Oaks."
James Fanshawe said of Dandino: "I thought the ground might be plenty quick enough but he ran a good race."