Aidan O'Brien has revealed he will likely rely on Los Angeles and Continuous in his search for a third Qatar Prix de l'Arc de Triomphe at Longchamp on Sunday.

Aidan O'Brien left five horses in contention following Tuesday's forfeit stage but with the ground set to be on the easy side, Los Angeles and Continuous are expected to lead the charge.

Auguste Rodin's participation would rely on good ground, while Opera Singer could yet drop back in trip for the mile-and-a-quarter fillies and mares only Prix de l'Opera. Luxembourg is also an unlikely runner.

"We think the most likely two will be Los Angeles and Continuous as both horses should handle the ground," said O'Brien. "We think the ground will not be good enough for Auguste Rodin and Luxembourg and the filly might go to the Opera instead."

After finishing a staying-on third behind the Breeders' Cup Classic-bound City Of Troy in the Epsom Derby in June, Los Angeles quickly became a Derby hero of his own when landing the Irish equivalent at the Curragh later that month. He followed that up with a hard-fought victory over St Leger Stakes runner-up and stablemate Illinois in the Great Voltigeur at York in August, before keeping on well to finish fourth when dropped back to a mile and a quarter for the Irish Champion Stakes last month.

"After the Irish Derby, we thought he could be a Leger horse, but we had other horses obviously for the Leger as well. So, it was in our heads he could be an Arc horse, so that's why we went to York to get a run into him and then drop back for the Irish Champion. That's kind of been the plan for a long time."

On his effort in the Irish Champion Stakes, O'Brien added: "We were very happy with his run in the Irish Champion Stakes, we were hoping if he finished in the first four that would be good enough to run in the Arc.

"Everything has gone well so far, and his work has been as good as expected."

Sunday's Qatar Prix de l'Arc de Triomphe will see the son of Camelot step back up to a mile and a half and with proven form going right-handed, O'Brien believes his three-year-old definitely has what it takes to be competitive.

He said: "He's a very big horse and we think he's improving physically. There's no doubt a mile and a half will be right up his alley, he's won an Irish Derby which is right-handed like Longchamp. We're very happy with his prep, he won the race in York (Great Voltigeur) before going back to a mile and a quarter in the Irish Champion Stakes. Hopefully, we've done as much as we can for him to run a good race."

Los Angeles is expected to be joined by stablemate and last year's fifth Continuous, who made the running when third in the Group 2 Qatar Prix Foy over the Arc course and distance last month.

"We were very happy with his last run, it didn't suit him making the running, but it was obviously going to be a slowly run race," explained O'Brien. "We think he's going to be much better in a strongly run race and we're happy with him. We've trained him with an autumn campaign in mind."

He added: "Last year's race (where he finished fifth) was a very slowly run race, so we were very happy with him. We've always had in our mind that he will be better this year and that we can prepare him better for the race."

As was the case in his prep run, Continuous could be set to be partnered by leading French rider Christophe Soumillon once more on Sunday.

"Christophe rode him last time so it's very possible he could ride him again. We do have five left in, but it will depend on ground and if one other will run."

Although Opera Singer looks unlikely to take her chance in the middle-distance showpiece at Longchamp on Sunday after finishing fifth in the Qatar Prix Vermeille, O'Brien's filly does still have the option of the Prix de l'Opera, staged earlier on the card.

"We were a bit confused with her last run," said O'Brien. "We thought she was going to stay but just ran a bit lacklustre. I don't know if she just got back a bit or found the track a bit funny so she will do a little bit of work in the morning, and we'll see how she is."

"The intention of running in the trial was that we'd go back for the Arc but after the trial, we weren't sure what happened. We could go back for the Opera, which is obviously the easier option. We're a little bit unsure and will see how she works in the morning."