It's an unprecedented eighth win for the Irish trainer at the Newmarket Classic
Aidan O' Brien has won the 2000 Guineas at Newmarket for a record eight time with his colt, Churchill.
The 6-4 favourite was steered by jockey Ryan Moore and was also on board his last 2000 Guineas winner - Gleneagles - in 2015.
The three-year-old finished ahead of Barney Roy and Al Wukair.
Churchill sat third at the halfway point in the race, but reeled in his two main rivals to win by a length.
The victory eclipses the achievements of legendary trainer John Scott and after the race O'Brien told Racing UK's Lydia Hislop that he was a little apprehensive about bringing an inexperienced horse into such a big race.
"Obviously we were a bit nervous coming here with him," O'Brien said. "He's a big horse in his first big run and it was a very competitive race.
"Everyone was happy with him at home, so that gave us some confidence to come here. But you're still worried coming here without a run. I think Ryan was very happy with him."
Ryan Moore and Churchill finish first in Saturday afternoon's 2000 Guineas at Newmarket. Image: Jon Buckle/PA Wire/PA Images
O'Brien said the ride was expertly guided by jockey Moore, who knew prior to the race how he would approach the showpiece.
"He said going out if the pace going out wasn't quick, it was going to be handy. If the pace was fast, he would take his time.
"I think it went to plan for [Churchill], we're delighted with him."
He added: "He was a big mature horse last year. When a horse is that big, you're always worried about him going from two to three. But he's a big imposing horse with an unbelievable mind."
Ryan Moore is led into the winners enclosure on Churchill after victory in the 2000 Guineas race during day one of the QIPCO Guineas Festival at Newmarket. Image: Jon Buckle/PA Wire/PA Images