Yeats ensured his place in the pantheon of racing greats as he became the first horse to register four glorious victories in the Ascot Gold Cup.

Since its inauguration in 1807, only Yeats and Sagaro in the 1970s had managed to visit the winner's enclosure three times, but Aidan O'Brien's veteran broke the mold in emotional scenes under Johnny Murtagh.

Faith in the old warrior had wavered after his defeat on bottomless ground in April, although the bookmakers had kept him on their side and the eight-year-old was always to the fore of the ante-post market.

Royal Ascot racegoers steamed into the entire on the day and he jumped from the stalls as the heavily-backed 6-4 favourite.

Murtagh always had Yeats handily placed and bustled his mount up to lead passing the three-furlong marker, as the sell-out crowd started to roar.

The Ballydoyle raider swung the bend in command and after opening up a substantial lead he ran strongly to the line to pass the winning post three and a half lengths clear of Patkai, with old foe Geordieland in third.

O'Brien said: "Unbelievable - that's all I can say. He is an amazing horse.

"I was so sick this morning as I believed this couldn't happen. I really felt sick to the stomach.

"History is very hard to change, we knew we had a wonderful horse but usually fairytales don't come true.

"You dream and dream and dream, we were in this position and we never would be again - great things can happen.

"This is something that has never been done before and I didn't think it could be done.

"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.

"He's an unbelievable horse and we knew there would never be another one of him."

Reflecting on his uncharacteristic performance at Navan in April, O'Brien added: "Like us all we don't think we become lazier with age, but we become wiser and do the same things every day with as little effort as possible - but he knew Ascot was coming.

"I felt pressure with Istabraq and got over it, and I thought it would never happen again.

"I was afraid of the disappointment for everyone if it didn't happen today.

"I can't tell you how privileged I feel but it is the people involved everyday that have made it happen - I was just watching from the distance."

Sky Bet and William Hill quote Yeats at 5-1 for a fifth Gold Cup, but O'Brien said: "I don't think he will try and make it five, but it is not my decision.

"He has an amazing heart and lung capacity - I don't know what would happen if anything ever happened to him.

"He is not gelded so we can tap into those genes, and I'd be afraid to race him again after today."

Murtagh was winning the race for the fifth time and the second time aboard Yeats, in the process taking his tally for the week to four to lead the jockeys' championship.

He said: "Muhammad Ali told everyone he was the greatest and he was, and Yeats has shown everyone he is the ultimate heavyweight champion.

"I had no doubts. After Navan I looked at Aidan and he told me 'he'll be grand for Ascot'.

"We kept saying the ground was too soft at Navan but nobody believed us and people tried to pick holes in him.

"He loves fast ground, he loves Royal Ascot and he comes alive here.

"This is one the greatest days of my riding career and the feeling I had coming past the line for the horse alone was incredible.

"I've had a good week but for the horse to win four Ascot Gold Cups is fantastic.

"It's good for racing, and Yeats is everything that's positive about racing."

Coolmore supremo John Magnier suggested Yeats' racing days may not be over yet.

He said: "To be good at anything you have to keep repeating it, and this horse has been doing it at Group One level for a long time.

"It is a great credit to the trainer and everyone who rides him as it is hard to keep a horse sound and have him right for a particular day.

"The trainer was always happy and the Gold Cup is run here in June, it is not in Navan in April.

"There will be no decision about his future today as we don't want to say something and do something else."

Asked about racing again this season, he said: "I thought that coming here if it went well - why would you stop with a horse that is enjoying himself like that?

"That's only my reaction, but people enjoy seeing him, he enjoys racing and we enjoy going racing with him.

"What would the point be in not going to somewhere like Goodwood? They look after us very well there too.

"It doesn't get any better than this. It's as good as it gets in the game."