Aidan O’Brien believes the best is still to come from last season’s Coventry Stakes winner River Tiber.

He suffered a scare in the days leading up to him finishing third to Vandeek in the Prix Morny at Deauville and then filled the same position behind the same horse in the Middle Park.

O’Brien felt he was not at his best in either race, though, and he was also a late withdrawal at the Breeders’ Cup, when he was meant to take on his stablemate Unquestionable in the Juvenile Turf, who ran out the winner.

“River Tiber always worked very good. He wasn’t right in Deauville or in the Middle Park, he wasn’t 100 per cent, so there’s a good chance there’s more to come from him. I think he’s a miler, he’s fast, I couldn’t see him getting much further,” said O’Brien.

“Unquestionable could go to the French Guineas, he’s done very well. He’ll go to Naas on Sunday (after racing) and he could go for a trial in France before going back for the Guineas – and he could be a French Derby horse, he’s not as quick as the others, so he could get a bit further.

“When we went to America with them last year, River Tiber was five lengths better than the winner. He’s not rated that way, but if you put the two of them together, that is what will happen.”

Another promising colt for the season ahead is the unbeaten Henry Longfellow, who could also have the French Classics on his agenda.

“Henry Longfellow could stretch out but he looks like a miler the way he’s going, so how much further he’d get, I’m not sure,” added O’Brien.

“He could be a French Derby horse, as could Diego Velazquez, he might be more that than a Guineas horse, but he’ll go with them (to Naas) as well, so it will be interesting.”

One going further afield is Henry Adams, who is heading to Dubai.

“Henry Adams is lovely and has done very well and he is down to go to Dubai to run in the UAE Derby on the dirt. He’s a No Nay Never so will be interesting on the dirt,” said O’Brien.

As for his Derby team, as usual there are several who at this stage would appear to have all the right credentials.

Leopardstown winner Ocean Of Dreams, from the family of the great Urban Sea, is certainly bred for the job.

“Ocean Of Dreams is getting ready for the Ballysax. He worked yesterday and worked lovely but he’s a bit of a baby because he’s only had one run, so he needs to get out,” continued O’Brien.

“He looks a lovely horse, he won very easily. He has a very good pedigree, he goes back to Urban Sea, I think he’s a Derby trial horse, no doubt about that.

“Los Angeles is a big, strong, powerful horse. He always worked much quicker than he should have been from the day we started working him, he showed loads. He’s very big and shouldn’t have shown as much as he was, but he always did.

“Then he ran in Tipperary and won in Saint-Cloud and Christophe (Soumillon) was impressed the day he rode him. He’ll go for a Derby trial and we’ll see what will happen. He’ll probably go to Naas on Sunday as well. He could be a Curragh (Irish Derby) horse.

“Grosvenor Square could be a very interesting horse. I think he’d have no problem with better ground. He’s not a heavy-framed horse, he’s a good mover. He’ll go for a Derby trial.”

As for the fillies, O’Brien was dealt a blow when news broke recently that Opera Singer, undoubtedly the best prospect in the division, was likely to miss Newmarket, but there are other options.

“Content was impressive last year, she had a lovely run first time but then went to Ascot and lost her way, we had to slow her down and get her to relax,” said O’Brien.

“She won at the Curragh and came home very well (fourth) in the Breeders’ Cup. She could be a very nice filly, you just have to take your time with her, as she has plenty of speed.

“I like Ylang Ylang a lot. She did very well to do what she did because everything went wrong with her the third day, she was too keen. She had to come back to Newmarket and relax but then to go back and do what she did in the Fillies’ Mile, you’d have to like her a lot.

“She could get a mile and a half, she’s out of a Shamardal mare, so there’s every chance she could and the way she likes to be ridden will help her.

“I don’t think if Opera Singer was going to make the Guineas it would have been a difficult choice for Ryan (Moore) though, she (Opera Singer) is very good. What she did in the Boussac…she’s another Justify, set her off in front and follow me if you want.

“The other filly is very good but you have to take your time with her. That’s what makes the Justifys so good, they are so uncomplicated.

“Opera Singer is cantering but missed a few weeks, so I imagine the Irish Guineas would be the earliest, we’d just have to rush her too much otherwise. The year is long.”