The highly regarded three-year-old was a leading fancy for the season’s Classics even before his encouraging third in the 2000 Guineas at Newmarket.

A setback ruled him out of the mid-summer contests but Luxembourg reappeared with a workmanlike success in the Royal Whip Stakes in August and he was expected to take a big step forwards from that run.

Luxembourg didn’t disappoint in a strong renewal. Stablemates Stone Age and Broome were left to their own devices in front and the former was still four lengths clear passing the three furlong marker but weakened with his job done as the field closed him down at the two post in the straight.

Onesto had raced close to the winner in the first part of the race and briefly hit the front, challenging between Stone Age and Luxembourg, but was soon worn down by the winner who had pulled half a length clear at the line.

Vadeni and Mishriff raced in the last two places and struggled to land a blow but the former, winner of the Eclipse at Sandown, finding his route blocked on his outside and in front, made a dramatic switch left-handed up the inside of Stone Age under Christophe Soumillon and snatched third, never nearer than at the line.

Mishriff was fourth with Stone Age fifth.

O’Brien was winning the race for the fourth successive year while it was a third success in four years for Moore who said: “It hasn’t been a straightforward year for him. He had a lovely run in the Guineas but wasn’t right afterwards.

“It was a good, fair race. He’s beaten some good three-year-olds and some good older horses. He always felt like he was in control of the race but was a little bit green. The Frankel horse was always there but I always felt I had him. A very professional, likeable performance.”

The Prix de l’Arc de Triomphe is an obvious end of season option and Moore doesn’t believe Luxembourg will have any difficulty in handling a step up in distance.

“He was very comfortable at 10 today,” he answered. “I always felt if I had to ask him for a bit more, he would have found a bit more and I don’t think a mile and a half would be a problem.”

Luxembourg is a 6/1 chance for the Prix de l’Arc de Triomphe with Coral.

O’Brien gave due credit to his team that helped get Luxembourg’s season back on track, saying: “It was unbelievable from a lot of people (to get the horse back) and Ryan gave him an incredible ride. We felt going to the Curragh (for the Royal Whip) that he was only ready for a racecourse gallop.

“He couldn’t come here unless he’d had a race, and that’s why we were so happy with him at the Curragh. He had 20 to 30 per cent to improve from the Curragh, and you usually don’t run a race in a Group race like that.

“The plan and the dream was, if we could get him back, we’d mapped out three races for him – if we could get him to the Curragh he could come here and if he came here he could go to the Arc. The pace was solid and it was an even pace. He’s obviously a very good horse.

“Ryan nearly fell off him in the Guineas (after stumbling leaving the stalls) and he was only beaten a couple of lengths. He had to be a bit different to do what he did in the Guineas. He wasn’t surrendering at the line today and he could be better over a mile and a half. His head was in the cooker a long way up that straight and he didn’t stop.

“Ryan was very impressed and he’s not an optimist by nature! Usually if he’s a little bit impressed that will do.

“I don’t think we have had an atmosphere at a Flat meeting in Ireland like this in a long time. He got applauded as he went out which is very rare.”

Soumillon, speaking after victory aboard Jadoomi, professed himself satisfied with Vadeni’s run in third.

“I was very confident always, I was behind Ryan, he was a bit keen, not over-racing but I feel he was a bit fresh today,” he said.

“He had a little blow at that stage (when Mishriff moved up on his outside), it was a bit early for him (to make his move) and I took the option to go between horses. He quickened quite well but I don’t think he was a hundred per cent fit.

“It was a good race today, of course, but there are some big races still to come this season. I could feel the horse when he had that little blow, he didn’t do that in the French Derby or at Sandown, so I wanted to give him more cover. He ran good, he finished in front of Mishriff again.

“The ground was a little bit loose on the top today and I don’t think that’s the best for him, I’m sure he prefers it when the ground is better.”