Zagora, trained by Chad Brown and ridden by Javier Castellano, won the $2 million, 1 1/4-mile Breeders' Cup Filly and Mare Turf on Friday.
Marketing Mix was second and favorite The Fugue, trained by John Gosden at Newmarket, settled for third as jockey William Buick found little room to run in the stretch.
With Star Billing setting the pace followed by Marketing Mix and In Lingerie, Castellano had Zagora lying fourth much of the way.
As they turned for home, The Fugue was trapped inside and Castellano took full advantage to power home.
Ridasiyna, another highly regarded European runner, closed strong to finish fourth as the 5-1 second choice.