Duke forward Cooper Flagg celebrates after scoring during the Blue Devils’ 93-49 win over Mount St. Mary’s in the first round of the NCAA tournament on Friday in Raleigh, North Carolina. Chris Carlson/Associated Press

RALEIGH, N.C. — Cooper Flagg had long watched March Madness and imagined being a part of it.

A sprained ankle suffered last week wasn’t about to delay that dream for Duke’s freshman star from Newport.

“I mean, this is something that I’ve dreamed about since I was 6, 7 years old, watching every single year with my family, my friends,” Flagg said.

In other words, there was no way he was going to sit out the top-seeded Blue Devils’ first-round romp against 16-seed Mount St. Mary’s on Friday, short of being on crutches, in a cast or unable to even stand on that left ankle. He had missed the past two games with the injury suffered during the Atlantic Coast Conference Tournament but looked comfortable and unbothered in his NCAA Tournament debut.

Flagg finished with 14 points, seven rebounds, four assists and two blocks in 22 minutes of work, finishing a team-best plus-31 before getting an early end to the workday with victory in hand.

Duke forward Cooper Flagg scored 14 points and grabbed seven rebounds in his first NCAA tournament game. Chris Carlson/Associated Press

“Honestly for me, after watching the whole ACC Tournament, it was more of just like a plan to just be ready for this game, and we just put a plan in place,” Flagg said. “We have phases, a strategy of just getting back, getting prepared, and being ready.”

The 6-foot-9 Flagg is a potential No. 1 overall NBA draft pick and was selected unanimously as an Associated Press first-team All-American, blessed with an all-around game that can make him a game-changing threat as a scorer and playmaker.

All at the age of 18.

And the Blue Devils need him if they want to make good on a seasonlong quest to win their sixth national championship. So even though the Blue Devils were likely set for a blowout against an overmatched foe, there was still a lot riding on what Flagg could do on the court.

The good news for Duke was that Flagg — greeted by loud cheers and a call of “Cooooooooop!” during introductions — provided quick answers.

His first basket came when he took a feed from Tyrese Proctor and banked it in on a drive while being fouled by Xavier Lipscomb, sending Flagg to the floor flat on his back. He landed with his fists clenched and his arms in a light flex that has become a go-to celebration move, then nodded as though getting the contact had welcomed him to the fight less than two minutes into the game.

Minutes later, he made a backdoor cut to take Patrick Ngongba’s feed for a dunk.

“I thought he looked pretty good,” freshman teammate Kon Knueppel said. “He was sharp.”

Flagg’s every move was watched closely by home-state fans, his teammates and coach Jon Scheyer.

“The biggest thing for me was him not pacing, I didn’t want him to pace,” Scheyer said. “Then obviously making sure he was moving, where he wasn’t off-balance of favoring one leg or the other.”

Flagg checked out for the final time at the 10:53 mark with Duke up 32, then spent the final minutes hopping around, laughing and cheering on the reserves getting mop-up duty to close this one out.

Duke forward Cooper Flagg played 22 minutes in his first game since an ankle injury suffered in the quarterfinals of the ACC tournament. Chris Carlson/Associated Press

“We were ready for him to play more,” Scheyer said. “But I think the way it worked out obviously was really good.”

Flagg got hurt when he rolled his ankle after having his foot clip the foot of a Georgia Tech player as he came down for a rebound in the ACC quarterfinals last Thursday. Flagg watched from the bench the rest of the tournament alongside versatile defender Maliq Brown, who went down with a shoulder injury moments before Flagg’s injury.

Still, Flagg was healthy enough to climb the ladder and snip a piece of net after Duke’s title win last weekend.

Scheyer said Flagg had spent time in a swimming pool using an underwater treadmill in the days after the injury. Flagg had said Thursday he was ready to go after building up more activity, which included returning to full practice Wednesday.

That’s why Flagg’s anxiousness Friday had nothing to do with his ankle.

“I didn’t have any doubts in my ankle at all,” he said. “But I definitely had some jitters. Like I said, this is something I’ve dreamed about since I was a little kid.”