CHAPEL HILL — Inside a jubilant North Carolina locker room on Saturday afternoon, the Tar Heels did something they hadn’t yet this season: They danced. They jumped. They celebrated a close victory against a quality opponent, and there was coach Roy Williams, right in the middle of the scrum.

“That’s what you coach for,” Williams said later, following his team’s 79-73 victory against UNLV. “… Those are the kinds of moments that I coach for so I can see kids enjoying themselves and feeling some satisfaction of doing some things that were fairly difficult to do.”

Entering Saturday, North Carolina had practiced 47 times this season. The Tar Heels had played 12 games. Yet until a tense, emotional victory against the Rebels, the Tar Heels had found few reasons to savor the moment.

There had been three humbling losses against Butler, Indiana and Texas. Blowout victories against teams that posed few challenges. And then came Saturday, when the Tar Heels built a 15-point, first-half lead and then turned away the Rebels during a dramatic second half that at times had the Smith Center crowd on its feet and roaring.

After trailing by nine at halftime, UNLV briefly took a one-point lead during the second half. Then James Michael McAdoo, the Tar Heels’ sophomore forward, scored six consecutive points to put North Carolina back in control.

The Rebels trailed by just three points with 30 seconds to play, but P.J. Hairston, the sophomore guard, made a pair of free throws that provided the Tar Heels with some comfort. Hairston provided a lot more than that, too.

Starting in place of Reggie Bullock, the junior guard who didn’t play while he recovered from a concussion suffered earlier this week, Hairston finished with 15 points, four steals and plenty of hustle plays that didn’t find a home in the box score.

In some ways, he personified his team’s gritty, gutsy effort. If ever there was a time for North Carolina to play with a purpose and urgency, “This was the game to do it,” Hairston said.

“We punched them in the mouth,” he said of the first half, which the Tar Heels controlled throughout. And then North Carolina hung on while the Rebels steadied themselves and made run after run during the second half.

Hairston’s performance pleased Williams. So, too, did the Tar Heels’ production on the interior, where UNC outscored UNLV 40-32 in the paint. Brice Johnson, the freshman forward, finished with 12 points in 15 minutes, and he blocked three shots. Desmond Hubert played a season-high 20 minutes and blocked three shots.

And after a quiet first half, McAdoo asserted himself in the second and finished with 13 points. Six of those came in direct response to the Rebels’ surge early in the second half that gave them a 49-48 lead with about 14 minutes to play.

McAdoo said later that Williams and others have told him to attack, and not to settle for perimeter jump shots.

“And that’s really something I just tried to do is really just not settle and really try to get their big guys in foul trouble,” McAdoo said. “I think a couple of them fouled out.”

Two of UNLV’s post players – Justin Hawins and Mike Moser – did foul out. North Carolina has attempted too many 3-pointers for Williams’ liking at times, but on Saturday the Tar Heels took just 10 3s and instead tried to go inside, either by pass or by penetration.

“When you shoot a lot of threes, you don’t get fouled a lot and you don’t get a chance to get a lot of easy baskets,” said Marcus Paige, the freshman point guard. “… In the second half, once we got into the bonus, we decided that we didn’t want to shoot a lot of threes, because we could have capitalized at the free throw line.”

Paige finished with 12 points and four assists, but he made a costly mistake with 30 seconds remaining when he fouled Katin Reinhardt on a 3-point attempt. Reinhardt made two of the three free throws, which cut UNC’s lead to 76-73, but Hairston made both of his free throws on the other end.

After UNLV’s Anthony Marshall missed a shot with 17 seconds to play, the Tar Heels played keep away and ran down the clock until the Rebels fouled Dexter Strickland, who led UNC with 16 points, with four seconds remaining.

Strickland described the victory as a “confidence-booster” for a team that entered Saturday needing some.

“They’re a top-20 team, they’re real good. And we kind of owed them for last year, when they beat us up,” Strickland said, referring to the Tar Heels’ 90-80 loss against UNLV a season ago. “But it was a big game for us. A chance to show everybody the potential that we have to be a great team.”

The Tar Heels showed that at times on Saturday. The held the Rebels to 37.9 percent shooting during the first half, and Williams said that represented his team’s finest defensive effort of the season. Then, in the second half, North Carolina persevered in a tight, competitive game – the kind it hadn’t yet experienced.

On an afternoon of firsts – first win against a ranked opponent, first experience in a close game – the Tar Heels experienced another afterward: They watched Williams jump out of happiness, instead of anger.

“I’ve never seen him jump around before,” Johnson said with a smile. “I’ve only seen him yelling.”

Carter: 919-829-8944 Twitter: @_andrewcarter