Irish colt Camelot kept his unbeaten record intact with a superb victory in the Investec Derby at Epsom.
Aidan O'Brien's 2000 Guineas hero was sent off the 8-13 favourite to complete the classic double.
The trainer's jockey son Joseph, 19, was happy to sit towards the rear for much of the mile-and-a-half journey.
For a moment in the straight it appeared his stablemate Astrology had stolen a march, but Camelot mowed him down heading towards the final furlong and went on to a five-length success.
Main Sequence narrowly denied O'Brien a one-two, getting up on the line to edge second.
It was a third win in the Epsom classic for the Ballydoyle trainer and his first since High Chaparral took Flat racing's greatest prize a decade ago.
He has now saddled the winner of all four Classics run in Britain this season.
Joseph O'Brien said: "I was a bit worried as he didn't come down the hill at all. He didn't handle the track that well, so he did well to win.
"He's a very special horse and I'm just very fortunate to be on his back. I owe a big thanks to the owners and everyone in the yard."
The winning trainer added: "You can't even dream of days like this. I was always happy, I know his (Joseph's) body language by now and he looked confident.
"No-one can describe the feeling, things like this don't happen."
Camelot could now bid to become the first horse since Nijinsky in 1970 to land the Triple Crown with victory in the St Leger at Doncaster in September.
O'Brien went on: "We'll give it a lot of thought and the boys will make a decision. The Triple Crown would be incredible."
Part-owner Derrick Smith said: "This is the one everyone wants in racing. To win the Epsom Derby is a dream come true.
"You could see from the three pole it was all over. It (the Triple Crown) must be (on the agenda), mustn't it?"
Coolmore supremo John Magnier added: "We are fortunate to have anything to do with him, and it's particularly important in the year his father (Montjeu) died.
"We are going to have to take it race by race and give it lots of thought.
"These things get to mean more as you get older. If you had asked me 30 years ago I might have looked the other way, but we will have to see what Derrick (Smith) and Michael (Tabor) say about it."
