Saturday's result gave the Ballydoyle trainer his sixth winner in the Curragh Group One in the past seven years.
There was drama early in the contest as 11-8 favourite Bradsell appeared to stumble coming out of the stalls, but it was Little Big Bear who was sent to the front by Ryan Moore in the early stages.
The 13-8 shot was shadowed by Richard Hannon's Persian Force, who at one stage appeared to be travelling better than the son of No Nay Never, but as the UK raiders loomed large passing the two-furlong pole, the Anglesey Stakes winner was just beginning to slip into top gear and was soon accelerating away from his pursuers.
Daylight was the biggest danger in the final furlong with the youngster recording a seven-length success over Persian Force, with Shartash, who did his best work late, another half-length back in third.
The victory not only brought up a hat-trick for the highly-talented two-year-old, but also O'Brien's 17th success in the six-furlong contest and the layers were suitably impressed, with the colt made favourite across the board for next year's 2000 Guineas.
O'Brien said: "He's a big, powerful, strong horse. He cruises and quickens.
"Before the race we had a bit of a scare with him when he came up here. He kicked a wall and the clip of the shoe went into his foot. He was a little bit tender when the shoe was put back on.
"It could have gone either way very easily, so it was a great call by John Halley and Lynn Hillyer to let him run.
"Ryan said when he let him go it was all over. He'd been progressing from every run. He ran here the last day with the view of going for this race.
"He loves good ground so he can show his speed. It was a very good race, but he has serious class. From day one we thought he was a bit special.
"At Ascot we thought he would get away with five (furlongs) even though we were happy going six with him.
"The lads can decide what they want to do. He has plenty of options and he can do anything, I suppose.
"I'm not sure we ever had one to do that in this race. It was a deep field."
Speaking further to Racing TV on potential plans, O'Brien raised the possibility of a fascinating clash with his elders at York later this month.
He said: "He has a lot of options and the lads can decide what they want to do with him, they could go to the Morny with him, they could go to the Nunthorpe. I don't think he's short of pace in any way, he's strong and he's mature.
"He could go to the Middle Park or the Dewhurst."
He added of son Joseph O'Brien recording his 1,000th career winner as a trainer earlier on the card: "I'm over the moon for Joseph. I know how hard he works, it's every day 24 hours."