Donnacha O'Brien punches the air as he wins the 2,000 Guineas on Saxon Warrior

Father and son were separated by the Atlantic Ocean but united in a momentous moment made on the Rowley Mile, where Saxon Warrior's storming display in the Qipco 2,000 Guineas gave Aidan O'Brien the 300th top-flight Flat triumph of his career and 19-year-old Donnacha O'Brien a precious first Classic.

In emulating his elder brother Joseph, who steered Camelot in the same Derrick Smith silks to teenage Guineas glory six years ago, the youngest man in the O'Brien family achieved a major personal milestone that left his father excited in America, his mother crying in Newmarket and the Coolmore partners dreaming of the Investec Derby.

Saxon Warrior: runs out a smooth winner of the 2,000 Guineas under Donnacha O'Brien

The swaggering hunk of a horse that is Saxon Warrior is now odds-on with some bookmakers and no bigger than 11-10 to maintain his unbeaten record at Epsom, where further success could conceivably prompt connections to consider a Triple Crown challenge.

At Epsom and beyond it will almost certainly be Ryan Moore in the saddle, but while he was preparing to steer Ballydoyle stable companion Mendelssohn at Churchill Downs, Donnacha O'Brien was living up to the enormous responsibility placed upon him by the world's most successful trainer and the sport's most powerful racing empire.

Watch: Saxon Warrior strides to a serene success in the 2,000 Guineas

The romantics will have been cheering on the marvellous runner-up Tip Two Win, who excelled himself for Roger Teal, a trainer unaccustomed to the big time.

No trainer is more used to the big time than Aidan O'Brien – now with nine 2,000 Guineas to his name – and he seems sure to enjoy more big days with last year's Racing Post Trophy winner, a breakthrough British Classic winner for Japanese super sire Deep Impact.

Saxon Warrior leads the 2,000 Guineas field through the closing stages

In a contest in which Godolphin's eventual third Masar was backed into 5-2 market leadership, it was just over a furlong out that 3-1 shot Saxon Warrior led.

Joseph O'Brien jockey profile

Yet asked when he thought he had the 2,000 Guineas won, O'Brien said: "Last Thursday."

Showing as much composure after the race as he had during it, Donnacha explained: "He had been working very well. He has looked special all throughout the winter. We've made no secret of that. He is very, very good.

Stunning Saxon Warrior better than Churchill, Galileo Gold and Camelot

"He travelled beautiful today and I thought I was the winner the whole way. I probably got a bit excited at the two pole, gave him a squeeze and got there too early.

All smiles: a grinning Donnacha O'Brien heads back to the walkway following Guineas glory on Saxon Warrior

"He is an absolute monster of a horse, so, you never know, he could improve again. I was very impressed."

He added: "If I had to put my neck on the line I would say his optimum trip is a mile and a quarter. He is definitely not a slow horse but he is bred to stay, and he is very relaxed, so there's every chance he'll stay a mile and a half."

That will be tested at Epsom, where among his supporters will be Michael Tabor.

"Like night follows day," said Tabor when asked if he expects Saxon Warrior to go from the Guineas to the Derby.

Saxon Warrior has stamp of Derby winner after strong finish in fast-run race

"Obviously a mile is not his ideal trip, but with the speed and class Saxon Warrior has got, we were always hopeful the mile would be fine, which it proved to be.

"Aidan has said he will only improve, although he added the caveat he still thought he could win or run a very big race here. That's how special he thinks he is."

Getting a shot of the new champ: racegoers get a close-up glimpse of Saxon Warrior as the son of Deep Impact is led back into the winner's enclosure

So special, in fact, that when asked if he would be keen to see Saxon Warrior seek to do what Camelot so nearly did by capturing the Triple Crown – for which Ladbrokes make him a 3-1 shot – Tabor was noticeably enthusiastic in his answer.

"No question, I would think," he said. "Why not? It most definitely motivates me. I haven't discussed it with John [Magnier], Derrick or Aidan, but to me, yes."

View the Kentucky Derby card, for which Aidan O'Brien saddles one of the favourites in Breeders' Cup and UAE Derby hero Mendelssohn

As for Aidan, Tabor described him as "incredible" on being told this had been the trainer's 300th Group/Grade 1 win. Truth be told, however, of all the O'Briens, this was mostly Donnacha's day. Moreover, that is surely how they would wish it to be remembered.

"He gave the horse a wonderful ride – he's obviously very good," observed Joseph, while mother Anne Marie, fighting a losing battle to hold back tears, said: "It's incredibly emotional. I'm so delighted for Donnacha. He's very independent and he manages his weight very well. He's a great guy. We're very proud of him."

Donnacha O'Brien with Saxon Warrior after victory in the 2,000 Guineas

So they should be.

"If I hadn't won a Guineas I would probably be the disappointment of the family," joked Donnacha, before maintaining the polite, modest, self-deprecating tone so characteristic of his family.

"A huge thanks to Dad and all the owners for letting me sit on him," he said, adding: "Thankfully I didn't mess up."

He did not. That is why Donnacha O'Brien is now a Classic-winning jockey.

2,000 Guineas replay, result and analysis

Members can read the latest exclusive interviews, news analysis and comment available from 6pm daily on racingpost.com