Silasol led early tracked by multiple French group winner Tasaday and Secret Gesture but entering the straight faded out of it as Christophe Soumillon urged Tasaday into command. Dalkala moved from midpack to run with Tasaday and doggedly pursued the front-runner down the stretch, drawing even in the final strides before thrusting her nose in front to win a tight photo.
Thistle Bird uncorked a strong rally to take third, a neck back.
Trained by Alain de Royer-Dupre, Dalkala covered 2,000 meters (about 1 1/4 miles) in 2:09.03.
The 4-year-old Giant's Causeway filly earned an automatic starting berth in the $2 million Breeders' Cup Filly & Mare Turf (gr. IT) Nov. 2 at Santa Anita Park with her Prix de l'Opera win, a Breeders' Cup Challenge series "Win and You're In" race.
Dalkala has won two of five starts this year and came in off a third to Romantica in the Darley Prix Jean Romanet (Fr-I) Aug. 18 at Deauville. She added the first group I win to her record with the Opera victory and improved her overall resume to six wins from 11 career starts, including her triumph in the 2012 Qatar Prix de Royallieu (Fr-II).
Kentucky-bred Dalkala is out of French group III winner Daltaya, by Anabaa. Her second dam Daltaiyma is a full sister to European Horses of the Year and sires Daylami and Dalakhani.