The son of Sadler's Wells was bred for middle-distances and it seemed the greatest mile-and-a-half prize of them all could be on the agenda.

But a training setback denied this equine superstar a crack at the Epsom Derby where victory would have guaranteed an almost instantaneous future at stud.

Instead, Aidan O'Brien, his quiet genius of a trainer, decided to run Yeats over longer distances, culminating in yesterday's record-breaking victory which overshadowed a shock
66-1 winner for Yorkshire trainer Richard Fahey.

As big-race jockey Johnny Murtagh and Yeats soaked up the crowd's adulation, after turning the Royal meeting's most prestigious race into a regal procession, O'Brien was almost overcome with pride – and emotion.

"You dream and dream and dream, we were in this position and we never would be again – great things can happen," said the trainer. "I think Johnny had a lot of pressure on his shoulders and the way he handled it, and the way he rode it, it was something else. I couldn't believe it."

Owned by the Coolmore breeding operation, its supremo John Magnier raised the possibility last night that Yeats may be kept in training.

"It is a great credit to the trainer as it is hard to keep a horse sound and have him right for a particular day," said Magnier. "There will be no decision about his future today as we don't want to say something and then do something else."

Asked about racing again this season, Magnier said: "Why would you stop with a horse that is enjoying himself like that?"

Meanwhile every other trainer can only dream of being in Aidan O'Brien's position – including Richard Fahey.

It was that man Murtagh who provided Malton-based Fahey with his first Royal Ascot winner in 2000 courtesy of Superior Premium.

But it was the quietly-efficient Paul Hanagan who was in the saddle, and showing Murtagh-like qualities, when the unheralded Cosmic Sun won the King George V Stakes – the finale to one of racing's most historic days.

Beaten in each of his previous 10 starts, he was pushed up to challenge for the lead in the straight by a determined Hanagan.

The more strongly fancied Chiberta King came at him inside the final furlong, but Cosmic Sun – a 66-1 rank outsider – found plenty to score by a length and a quarter.

Hanagan, who was securing his first Royal Ascot winner, said: "We had our hopes up in the Queen Mary on Wednesday but Rose Blossom was disappointing and this shows how up and down the game can be.

"When he ran at Musselburgh last time, he ran out on the bend and didn't handle the track but he didn't put a foot wrong here."

Fahey added: "I couldn't say I fancied him at 66-1 – but he had run some good races."

tom.richmond@ypn.co.uk