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The Simon & Ed Crisford-trained filly Senorita Bonita came from well off the pace to reel in the runaway outsider Carry The Flag and storm well clear at the line.
The Duchess Of Cambridge Stakes winner had her Newmarket form franked by runner-up Libertango in the week when the George Boughey-trained filly landed the Lowther Stakes at York, and came into this Group One the 2-1 favourite in the British betting.
Carry The Flag was given an aggressive ride by Ronan Whelan from the stalls, and the 150-1 outsider had all-but-one of his six rivals in trouble approaching the final 200 metres.
Having been held up by Oisin Murphy, Senorita Bonita was the only one who was eating into the large deficit with any gusto, and once drawing alongside soon sprinted clear for the most authoritative of victories.
Norfolk Stakes winner Orthodox, the other fancied British runner, was more handily placed than the winner but failed to pick up on this first try at the trip, while Man's Best Friend – winner of the Richmond Stakes at Goodwood - never looked like bettering his stablemate Carry The Flag's efforts.
Instead, it was the local hope Kosuma who ran on for third, never nearer than at the line.
The win was a second in the race for the Crisfords following the 2023 success of Vandeek, and after the race Simon said: "She's got an amazing turn of foot. She was a bit slow away and a bit behind the bridle as they went quick.
"Her turn of foot is electric - she's a proper filly. We will head to the Cheveley Park against Sun Goddess and Libertango and that will be one of the highlights of the autumn season.
"We are looking forward to a three year old season - she could be a Classic filly.
"She is out of a mare who is by Ruler Of The World, a staying family. Physically she looks like a six-furlong filly, but next year we will definitely be trying her over a mile."
Murphy added: "Her work leading into the race was fantastic. I thought today her preparation was perfect.
"Simon never likes me taking my time too much, but Ed and I had planned to let her relax. She has a very good turn of foot.
"She has an awful lot of speed, who knows if she will stay a mile? If she does, then obviously she will be very, very good."