Aidan O’Brien duo heading for Newmarket.

Having made what he described as a "hash" of City Of Troy's 2000 Guineas bid twelve months ago, Aidan O'Brien is leaving nothing to chance as he gears up to saddle Twain and Expanded in the opening Classic of the season at HQ on the first weekend in May.

"I've looked under every stone, but hopefully, I didn't look under too many," said O'Brien at a press event organised by the Jockey Club.

"We hope we haven't over-trained them, which is always a possibility. We've done everything we should have done up until now, but hopefully, we haven't been too hard on them.

"I made a hash of him (City Of Troy) in the Guineas. The one thing I didn't do caught him, and it just went wrong.

"There are a few horses there that could be absolutely anything, and at this time of year, the water is very rocky because you're trying to have a little look at them without them knowing it and over-exposing them.

"That's the problem, whether you lean too hard on them or don't lean enough, especially as the Guineas comes early.

It's easy to overdo them as well as underdo them, but we think they're fairly right."

After ruling out ante-post 2000 Guineas favourite The Lion In Winter, who will now make his reappearance in the Dante Stakes at York, O'Brien is now putting his lightly raced duo of Twain and Expanded through their paces ahead of Newmarket.

Twain's stunning six-length debut success was followed up by a remarkable success in the Group 1 Criterium International at Saint-Cloud just eight days later, while Expanded almost completed a similar feat, winning first time out at the Curragh before going down by a neck to Charlie Appleby's Shadow Of Light a week later.

"It was probably impossible what we asked Twain to do," explained O'Brien. "He never saw a horse in his maiden, the plan was to drop him in and educate him a little bit, but he jumped out and that was it and won by six lengths, so he went to France after having a racecourse gallop by himself really and he was very green but still won very nicely,"

"Expanded was going to the Dewhurst for experience and then when The Lion In Winter came out, that put him as the number one, probably unfairly, and then when there wasn't many runners in the race, Ryan (Moore) ended up having to make his own running and he got into a duel with the third horse three furlongs down, so it was very hard on him what happened."

Although both horses are on course to run in the 2000 Guineas at Newmarket, O'Brien didn't rule out Expanded running in the Irish equivalent at the Curragh.

O'Brien said: "Obviously, Twain is a Group 1 winner, and what we thought is if the two are going very well coming up to it, we might let Expanded go to the Curragh the following Monday because he's not a Group 1 winner. He could start in the Irish Guineas trial (Tetrarch Stakes), and Twain could go straight into the Guineas."