It was stablemate Sergei Diaghilev who set a brisk pace at the head of the Group One field, before the race began to take shape as they hit the two-furlong pole, with all the runners on the stands side.

Ryan Moore and favourite Noble Exhibit put down their challenge a furlong and a half out, but Giant Sequoia (11-1) was travelling strongly upsides and really picked up when asked by Dylan Browne McMonagle, stretching three lengths clear of Andrew Balding’s staying-on Gran Dia.

It was a record-extending 13th success in the race for O’Brien, who had been happy to draw a line through the winner’s disappointing effort in last month’s National Stakes.

He said: “He disappointed the last day, but that was when our horses were off colour.

“I’m over the moon with him really, he travelled well, quickened very well and I’m delighted for everyone at home. It’s a big team effort.

“He’s very classy, he could be anything next year. He was just under the weather the last day. We gave him time, his work has been lovely.

“We weren’t sure about that ground, but you never know until you try. He’s very classy.”

O’Brien has won the Town Moor feature with three subsequent Derby winners and added of the Frankel colt: “We always thought he was a Classic horse, a mile or a mile and a quarter would be no problem, but he could get a mile and a half. His dam (Pink Dogwood) was very good and she stayed.

“We always thought he was very good, a proper horse. I’d say he’s a Guineas, Derby, French Derby horse, all those things.

“One of his owners is American (John Stewart), but we had four others for the Breeders’ Cup so we tried to space them out a bit!”

On Noble Exhibit, who was edged for second by Gran Dia, O’Brien said: “He was a bit green, he was running around a lot.

“He won making the running twice and probably didn’t learn a lot. Maybe in that ground he gave him the chance to run green and he got there and ran around a bit.”

While Browne McMonagle has been winning countless big races for O’Brien’s son, Joseph, this was his first Group One for the Ballydoyle handler.

“He’s a great rider, that’s all you can say,” said O’Brien.

The jockey himself said: “He’s a horse who has developed plenty throughout the year, he’s a big boy to sit on.

“The race worked out perfect, it was a nice even tempo and he relaxed. I felt like halfway on it was just a matter of sitting into him and he reacted quick.

“He quickened well and when I got to the front he was having a nice look, but he’s still a big baby and he’s going to be a lovely horse next year.

“Everyone was very complimentary of him and they said he was a lovely horse and going up to a mile was always going to be a help to him. I think he’ll get further in time and he’s very solid. He’s definitely a good horse.”

He added: “That’s a first Group One for Aidan, so a big thanks for the leg-up.”