Prix de l’Arc de Triomphe third Diamond Necklace could head to the Breeders’ Cup Turf at Keeneland if she comes out of her French trip well.
Despite being drawn widest of all in stall 16, she ran a big race to finish just behind Bay City Roller with Daryz a clear-cut winner.
O’Brien had countless placed horses over the two days, but had to wait until the final Group One of the weekend to be able to enjoy a winner in the Prix de la Foret with True Love.
“It was a long couple of days because we had some fancied horses and hadn’t had a winner before True Love, but it was tough racing,” he said.
“Diamond ran a stormer. She didn’t have a great draw, but she ran a great race.
“Christophe (Soumillon) said he was trapped three wide and he was delighted with the run. He said he would have preferred to have had a lead into the straight, rather than being in the lead, but she ran a great race and the winner is obviously a great horse.
“The funny thing about her is it’s only in the last month that she’s been able to take a normal horse’s work, so there’s every chance she’s been weak all year and is just starting to progress now.
“She could go to the Breeders’ Cup Turf and the lads could keep her in training next year, it depends what they want to do.”
Reflecting on his other Arc runners, Benvenuto Cellini and Minnie Hauk, who were ninth and 10th respectively, he said: “Benvenuto was a bit slow away so we’ll have to work on that if he’s going to the Breeders’ Cup Turf.
“Ryan (Moore) said he got back a bit further than he wanted and the pace was slow, but he was very happy with the horse’s run.
“William (Buick) said he was trapped in and again he said the pace was a little bit slow for Minnie, so she could go to the fillies’ race in Ascot.”
He added: “Overall I think you’d have to be happy the way they ran and Precise ran a good race in the Prix de l’Opera. She could drop back a furlong and go for the Breeders’ Cup Filly & Mare Turf.”