Castle Lady maintained her 100 per cent record with a convincing success in the Emirates Poule d’Essai des Pouliches at ParisLongchamp.
Unraced as a juvenile, Castle Lady only made her racecourse debut in March, when successful on Chantilly’s all-weather track.
She improved to take the Group Three Prix de la Grotte over this course and distance and progressed again to lift the Classic for Godolphin.
Commes was second for Jean-Claude Rouget, with Kevin Ryan’s North Yorkshire challenger East running a big race in third place.
Barzalona told Sky Sports Racing: "It's always hard. She had to pass one more step, but she's got a great mentality, she's got a beautiful action and a big heart, that made the difference.
"My filly settled well and picked up the last two and a half furlongs.
"When she picked up I thought I was going to win the race by five or six lengths, but in front she was a little bit green so that meant there is a lot more to come."
Castle Lady was cut to 9-2 from 6-1 for the French Oaks (Prix de Diane) with Paddy Power.