Lambourn delivers O'Brien record-extending 11th Epsom Derby
For O'Brien it completed an extraordinary two days as Minnie Hauk won the Oaks on Friday and his Jan Brueghel won the other Group One race, the Coronation Cup.
It is not the first time the 55-year-old has achieved the Oaks/Derby double, last doing it in 2020 with Love (Oaks) and Serpentine who like Saturday's winner also made all to win.
"It's been an incredible two days, I am delighted," said O'Brien after in his usual generous fashion he had rattled off a whole series of people who should share in the glory.
"This horse is: uncomplicated, genuine and committed. He always has been."
Jockey Wayne Lordan was never challenged in winning his first Derby on his ninth ride in the race considered to be the 'blue riband' of flat racing.
Lordan's career was in doubt a couple of years ago after a dreadful fall in the Irish Derby in which he suffered a fractured leg and elbow and was out of action for eight months.
"I had to go through a whole series of tests," he told English broadcaster ITV.
"I finally got the green light, but it was rather an odd way to tell me I could ride again.
"He said you are fit enough to take another fall. I knew if I had another fall it would the end of my career."
'Very disappointing'
Saturday, though, represented his biggest ever victory, although it came in front of what looked to be a disappointing crowd, a smattering of spectators populating the normally packed Epsom Hill on the inside of the track.
For Lordan -- "a great fella" opined O'Brien -- that mattered not a jot.
"It's one of the greatest races," said the 43-year-old.
"For any jockey that wants to start out, all they ever want to do is win the Derby and I work for Aidan, Ballydoyle, Coolmore so I'm in a lucky position that I get to ask a horse like this."
None of the other fancied horses landed a blow and it was two outsiders that were closest at the finish -- Lazy Griff (50/1) was second with 28/1 chance Tennessee Stud, trained by O'Brien's son Joseph, third.
"I knew I'd gone a good gallop, his ears were pricked and I knew he had plenty left," said Lordan.
"He's a horse that we've always felt stays well so I just thought anybody that gets to me will have to stay well and it'd be tough for them."
Lambourn more than made up for O'Brien's hugely disappointing race favourite, Delacroix.
He was in the middle of the 18-runner field initially but as they turned for home he was third from last, his jockey Ryan Moore telling O'Brien he had been bumped and never recovered from the impact.
He eventually finished ninth.
There had been hopes that the Aga Khan Stud-owned Midak would deliver a poignant win in a race named this year in honour of the late Aga Khan IV, who won the race five times.
However, although he raced in fourth for a long way when the moment came for jockey Mickael Barzalona to move up a gear on the French runner he went into reverse and finished 10th.
They at least got their chance to run, another of the favourites Ruling Court was pulled out less than two hours before the race.
It dashed hopes of him becoming the first colt (male horse) since Nijinsky in 1970 to win the classic Triple Crown -- the oldest classic St Leger in September the final leg.
"It's very disappointing," trainer Charlie Appleby told ITV.
"Stamina was an unknown for us and we felt that what we saw in the Guineas on quick ground and the way he quickened that day, it was not going to be the ground for him today to be testing him over a mile and a half."