The filly, winner of her first nine starts, failed in her bid for a perfect 10 when only fourth to Dubawi in the Prix Jacques le Marois on Sunday.
Connections of the Pascal Bary-trained daughter of Kingmambo believe it will be a couple of days before they will know for sure if they can pinpoint the reason for the dual Classic winner’s disappointing performance.
The five-times Group One winner is to be given a break before being trained for the Breeders’ Cup Mile at Belmont Park in October, which will be her next race.
“She has travelled home to Chantilly safe and well and she has eaten up,” said Alan Cooper, racing manager to owners the Niarchos family.
“She will have a rest and then go for the Breeders’ Cup.
“Pascal Bary is travelling back from Deauville today and he will have a look at her. It will be a day or two before we know if anything has come to light.
“She ran flat - it can happen.”
Meanwhile, Vodafone Oaks heroine Eswarah will have her second start since landing the Epsom Classic when facing 10 rivals in the Aston Upthorpe Yorkshire Oaks at York tomorrow.
Michael Jarvis’ charge lost her unbeaten tag last month, coming home eighth in the King George VI And Queen Elizabeth Diamond Stakes at Newbury.
The daughter of Unfuwain faces a strong challenge on the Knavesmire with John Gosden’s Fillies’ Mile winner and Irish Oaks runner-up Playful Act set to take her on.
Kevin Prendergast’s Right Key was fourth in that Curragh Classic having won her two previous starts and renews rivalry, as does fifth home Dash To The Top for Luca Cumani.
There is an international feel with French raider Shamdala trying to land a hat-trick in the Group One contest.
Lune d’Or also represents France, while Itoa will take her chance for Germany.
Favourita, second to Eswarah earlier in the season, has been beaten on her last two outings in Listed company and will be having her first crack at a mile and half in the £250,000 race.
Last year’s Oaks third and Ribblesdale winner Punctilious bounced back to form at Newbury last month and will bid to follow up, while John Oxx’s Hazarista - third in this race 12 months ago - again takes her chance.
The Richard Hannon-trained Aunt Julia, third to Punctilious last time out, completes the field.
Meanwhile, title-chasing rider Seb Sanders moved on to the 100-winner mark for the season with victory on Out For A Stroll in the Claxton Engineering 20th Anniversary Handicap at Yarmouth yesterday.
At Nottingham, Killarney Beauty after opened her account at Nottingham.
The daughter of Komaite (9-4) was scoring at the second attempt in the Nottingham Racecourse & Conference Centre Maiden Auction Stakes and was soon in front in the hands of Franny Norton.
She made the rest of the running in the six-furlong test before staying on gamely to hold the strong challenge of debutant Time For Life by a neck.
John Gosden and Jimmy Fortune are in red-hot form and they both took their score in the past 15 days to 16 when Mystical Land (13-8) landed the Letheby & Christopher Stable Staff Conditions Stakes.