Aidan O’Brien could offer no immediate excuse after City Of Troy’s bubble was well and truly burst in the Qipco 2000 Guineas at Newmarket.

The son of American Triple Crown hero Justify carried all before him as a two-year-old last season, with debut success at the Curragh followed by successive Newmarket raids as he pulverised his rivals in both the Superlative Stakes on the July Course and the Dewhurst on the Rowley Mile.

O’Brien, whose staggering Classic haul includes 10 2000 Guineas wins and nine Derbys, has never hidden the regard in which he holds City Of Troy, stating after his Dewhurst success: “We’ve never had a horse like him, that’s the way it is – he is the best two-year-old we’ve trained, there’s no doubt.”

Following a seemingly trouble-free run-up to his three-year-old debut, the crowds packed around the Newmarket parade ring to catch a glimpse of the much vaunted colt before he cantered down to post aiming to become the first odds-on winner of the 2000 Guineas since Frankel 13 years ago.

But while Frankel lit up Headquarters with a performance for the ages, 4-6 shot City Of Troy became upset in the starting stalls and while he jumped out quickly to grab the early lead, it was clear from halfway he was struggling to maintain the gallop and he weakened late on to finish ninth of 11.

“He got upset in the stalls before, which he never did before, then he jumped and Ryan just said the pace was on and he was in the middle of the pace and he just flattened on his first run,” O’Brien said.

“We’ll see, it was unusual he got upset in the stalls because he was very happy before. He was in last, but he wasn’t in last by design, that’s just the way the stall things fell.

“There’s no doubt about that (the run was too bad to be true), he wasn’t over-blowing. We’ll take him home and see, sorry about that.

“Of course (I’m shocked), obviously we wouldn’t be here if we thought he was going to do that. Obviously it’s not his run and we’ll see what happened and why it happened.”

While dreams of Triple Crown glory have gone up in smoke for City Of Troy, O’Brien can take heart from the fact Auguste Rodin failed to fire as a hot favourite for last year’s 2000 Guineas before bouncing back to claim Derby glory at Epsom and the Curragh.

The trainer added: “Everything was always straightforward with him, so we’ll try to find out what happened and try to not let it happen again, isn’t that it?”

Richard Hannon admitted to having mixed emotions after seeing Rosallion and Haatem finish second and third respectively.

The East Everleigh handler had been bullish about the prospects of his Prix Jean-Luc Lagardere victor Rosallion in the lead up to the first Classic of the year and he travelled powerfully for much of the way before having to give best late on to the impressive Notable Speech.

Rosallion’s Craven Stakes-winning stablemate Haatem also emerged with plenty of credit in picking up the bronze medal.

Hannon said: “Both my horses ran great races, I’m disappointed to get beaten but you can’t be disappointed by how they ran.

“Rosallion travelled so well and ran a huge race. I’m not going to lie, when I saw City Of Troy fading out of it I thought ‘there’s the main one gone’.

“I’m disappointed to get beaten, but maybe if he wins wherever we go now it will make it even sweeter.

“It’s probably one of the best Guineas there’s been for 10 years and both of my horses have shown they’re Group One horses – one (Rosallion) has won a Group One and the other one will, so there’s a lot to look forward to.”