City Of Troy proved the doubters wrong with an emphatic success in the Betfred Derby at Epsom on Saturday.

European champion two-year-old last year, City Of Troy was sent off a red-hot favourite for the 2000 Guineas at Newmarket last month but was beaten at halfway. Connections concluded that the horse's performance there was too bad to be true and kept the faith, confirming that the Derby would be next for the son of Justify.

It was a path trodden by Auguste Rodin last year and punters believed that trainer Aidan O'Brien could do it again with City Of Troy, sending him off the 3/1 favourite at Epsom.

Held up in mid-division by Ryan Moore, City Of Troy surged forward early in the home straight and his the front two furlongs out. Ambiente Amigo was alongside and appeared to be travelling even better than the favourite but he could not match City Of Troy who strode forward to win by almost three lengths.

Ambiente Amigo finished second, Los Angeles was third and Deira Mile was fourth.

It was a record-extending 10th Derby triumph for Ballydoyle maestro O’Brien, and a fourth win in the race for Moore. O’Brien also saddle the third home in the shape of Los Angeles.

O’Brien said: “The exciting thing for us is Justify (his sire); he has looked very special all the way and the class that they have, speed as well as stamina, is amazing.

“Ryan gave him an incredible ride and I’m so grateful to everyone for the work they have done.

“We knew the Guineas was totally wrong and I made mistakes training him, that’s the bottom line. There were stones I didn’t look under, he was too fresh, he was unprepared, he blew up, that’s the reality.

“But we learned from it and knew the ability he had – and since then everything has been beautiful.”

“In the Guineas he just went in and he charged the stalls and before he had a chance to get his breath back he was out and gone, and we feel his heart rate went too high, so that’s why he only got to halfway and that was the end. But we still weren’t sure until we took him back, and it was going to take two, two and a half weeks before we could get him to stage again where we would put him in the stalls, and we had a FitBit on him when he went into the stalls, and his heart rate went way above 240, standing in the stalls, so that for us - then we knew what happened in Newmarket.

“We had to give him time, the lads worked on him and the last time we took him back into the stalls he was as calm as anything. We were so delighted, and we were hopeful that that was the case, but because he officially didn’t play up in the stalls at Newmarket, he couldn’t get a ticket to go in late, which is right - it has to be in the rules, that, and he didn’t - and we had the whole thing that he would stay relaxed, and he did. We had two other horses in the race and both were mile and a half plus horses. We wanted a true-run race where everyone was going to get a true run. So we were going to find out whether he stayed and whether he was going to do things right and did he have the ability to come through. Ryan was very patient on him and gave him a beautiful, calm, relaxed ride. He said he was very green through the race because he was never dropped in before. A lot of stuff had to fall right for him.

“In sport everyone has their opinions, which they are entitled to, and negatives and positives, and he had a lot to lose today by running, but it happened and I’m so grateful to Ryan for giving him the ride he did, and to so many people. I’m so thankful.

“He did a lot of stalls work after we found out that was the reason. Dean rode him the first day in the stalls, and he said the minute he was in his heart rate was through the roof. Then the FitBit showed that. The next day I think Rachel rode him and the FitBit showed he was calmer - a totally different heart profile. It was very exciting when we found that, because other than that, you wouldn’t believe… what was the reason? Was he just a two-year-old who just lost his head and he wouldn’t get it back? I think I left him too fresh and I treated him probably with too much respect through the winter and wasn’t hard enough on him. We hadn’t put him into stalls because we never thought that something like this would happen - it’s another thing that goes on the list for horses going forward, that this has to be done, so you're learning every year, but the problem is, with a horse like that to make a mistake it can cost so much.

"Obviously, I was very sorry about it, but if you don't make mistakes you don't go forward.

"We're very sure that that was the reason now and we're very excited going forward.”

Asked if he felt extra pressure going into the race given how vocal he'd been about his belief in City of Troy, O'Brien said: "I was only saying what I thought. Maybe we shouldn't do it, but we always feel like ... today, we might not get to tomorrow. So there's no point in me thinking it today and keeping it to myself and nobody would ever get the good feel factor from it.

"So we always think as we feel at the time, and by doing that you're obviously always giving yourself a stick to get beaten with, but life is too short.

"We live one day at a time. We make a plan and we don't need to look any further than tomorrow. We forget about yesterday, and that's just the way it is, really.”

Asked about City of Troy's future, the trainer added: "There was a big plan drawn out for him. After the Guineas the decision was made to stick to the plan, and we would come here.

"The next plan made for him was we would go to Saratoga for a mile and a quarter race, and the lads will talk about that and they'll talk to Ryan and see what they want to do and then they'll give us their thoughts and set out a plan for it, and we will go that way.

"The only thing I'm not sure about is Ryan said he was very green today and whether he will be able to run into a race like that straight away I'm not sure.

"But Ryan will talk to the lads about that and they will make that decision.

"Obviously, looking at him today there doesn't seem to be any end to his stamina either, and that's what we really thought about him before.

“It will be very interesting, but it will be a hard decision for the lads to decide what they want to do and where they want to go with him.

Asked about him possibly stretching out further in a St Leger, O'Brien said: "You could, but, listen, he's very classy.

"Everything is open to him. His dad was unbeaten, a triple crown winner. To win a Belmont on the dirt, you have to get a lot further than a mile and a half. Unusual really, I think it's the stride and the class they have. They're very genuine.

"The Eclipse or King George - both would be open to him. When Ryan said he was that green through the race, that's probably going to have to influence their decision where they're going to go. Do they keep him at home, keep him on grass? And go one of those, or what.

"It won't be an easy decision to make.

“To be a winner of the Derby and be that green - I was surprised when Ryan said that, but no one would know better than Ryan. He’s a very good mover and when we ran him in the Dewhurst we weren’t sure it was the right thing, because he’s such a good mover.

“We all know how cruel sport is, and how cruel life is, and you can often have an opinion and say something and it might never be borne out. When you are prepared to perform and to put your hat in there, you have to be prepared to be shot down and that is just the way it is. If it doesn’t happen it doesn’t happen, and we’d have a lot of trips home and long journeys, but we are always happy when we get home and we know what happened, because then we know what to work on. The disappointing thing for us is never getting beat, it’s getting beat when we don’t know what happened. Then we don’t know what to work on and what to improve, but we felt with him that we were taught that at the races, but we weren’t sure until he went into the stalls at home again. The minute he did we were very sure that this what happened. It’s the people who around them who make all the tweaks and keep their focus and work so hard day in and day out - they are the people who make it happen, and we watch and listen and work it out. It’s a massive team thing.

“It’s incredible to have won 10 Derbies, but we don’t ever look back that far, we always try to stay in the minute and look to the future, although not too far ahead.

“We knew that Los Angeles would stay very well and that’s the way we rode him. We were going to expose City Of Troy if he didn’t stay.

“There’s more than a touch of relief - I’m delighted for everyone because they all had a lot of faith and they all put a lot into him. Everyone stood strong behind the team and the decision.”