A Group One winner at ParisLongchamp when last seen in May, Above The Curve was a 5/1 shot for Joseph O'Brien and Ryan Moore, with last year's victor La Petite Coco the even-money favourite for the 10-furlong feature.
Moore settled on the outside of La Petite Coco and was perfectly positioned to go for home when the favourite tried to launch a winning run a couple of furlongs out.
Above The Curve grabbed the lead and refused to relent, holding off the fast-finishing Insinuendo by a neck, with 66/1 shot Galleria Borghese a further length and a quarter back in third.
"I thought it was a fantastic ride from Ryan. It was the filly's first run back after a lay-off and I thought she'd come on a bit for the run," said O'Brien.
"She's a classy filly, a Group One winner, and I think her attitude really showed in the last 100 yards, she put her head out and fought it out.
"She's an impeccably-bred filly and I've been really lucky with the American Pharoahs, he's done really well here in Europe particularly.
"You could see this filly's attitude in the last furlong - when the going was getting tough she put her head out and fought all the way to the line, beating a very good filly.
"The plan was that this would be a nice stepping stone to the fillies' race on Arc day (Prix de l'Opera) and that should set her up lovely for that, she's a course and distance winner already."
When asked if she could remain in training next year, he added: "I think there is a chance that could happen. She's a big filly, she's actually 17 hands which for a three-year-old filly is incredible.
"She seems to have progressed from the spring and hopefully she can progress in the future."