Taghrooda's unbeaten record was brought to an abrupt end as the Aidan O’Brien-trained 8-1 shot Tapestry claimed a shock victory in the Darley Yorkshire Oaks.
After her heroics in the Investec Oaks and the King George VI And Queen Elizabeth Stakes, this latest Group One was expected to be little more than a warm-up for a probable challenge for the Prix de l'Arc de Triomphe.
Halfway down the long home straight, everything appeared in hand with Paul Hanagan still to play his cards, but Taghrooda was worn down by Tapestry and Ryan Moore as the 1-5 favourite went down by half a length.
Overnight rain had eased the conditions slightly to good from Wednesday's good to firm, but Taghrooda's first defeat in five starts had been handed out by a rival who is said by her trainer to demand quick conditions.
Tapestry had her own back story, and while her second-place to stablemate Bracelet in the Irish Oaks made good reading purely on paper, O'Brien knew it should really have been another first.
He said: "It didn't go right in the 1000 Guineas but there was a glimmer in the Coronation Stakes (sixth).
"She's come forward with every run and the last day in the (Irish) Oaks she stumbled coming out of the stalls and the saddle went out on her rump.
"It was hard to believe she went the whole race with the saddle where it was and still just got beaten."
O'Brien, fresh from Australia's Juddmonte International triumph, now has another star performer to pitch into the autumn championship races.
"It wouldn't matter where it was, colts or fillies, but ground would be vital," he said.
"If all fails you'd imagine you'd get fast ground at Santa Anita (Breeders' Cup) at the end of the year."
Asked if Tapestry could stay in training at four, he said: "The lads (Coolmore owners) will decide. It would be great but she's a Galileo and they are so valuable. There's always a risk you'll lose them."
Taghrooda can still head for Longchamp in October, and trainer John Gosden said: "No excuses, she's just been outstayed on the Knavesmire, which has happened to horses before.
"She was nice and relaxed through the race, he (Hanagan) gave her a lovely ride and it was a great race.
"The winner is just one of those fillies that has come to herself at this time of year. There was a lot of confidence behind her in the Irish Oaks and she had a problem with her tack, I believe.
"They've beaten the rest an awful long way, and she has just been outstayed.
"She's been in great form at home and barely had a race in the King George so there'll be no change to the plan, it will still be the Arc.
"They've always liked the winner, she has always been towards the top of their pecking order."
His views were echoed by Hanagan, who said: "I don't think there were many excuses, she was just beaten by a very good horse.
"We went a nice enough gallop, I got there and I thought it would take a very good one to beat me and I think one did. No excuses."
Moore had a Grade One double in America last weekend and this was yet another big race to tick off his list, even if he was given a four-day whip ban for his trouble.
He said: "She looked one of the best two-year-olds last year and it has just taken a while for her to come to hand, but she ran a very good race the last day and has improved again today.
"We had nothing to lose. So it (tracking Taghrooda) seemed the best play we had.
"She had to battle. The other filly had plenty of time to come back if she was good enough. They are two very good fillies - they were seven lengths clear and I think that says it all really."
Godolphin's Tasaday ran well for a 22-1 chance, and finished seven lengths further back in third.
Trainer Saeed bin Suroor said: "She ran a good race, and the softer the ground the better. She has a lot of options open to her over a mile and a half, both here and abroad."