DURHAM — Before he explained why he moved P.J. Hairston into North Carolina’s starting lineup on Wednesday night at Duke, Tar Heels coach Roy Williams scoffed at those who have questioned why Hairston hasn’t been a starter for a while now.

“I started to do it four or five games ago,” Williams said on Wednesday, after UNC’s 73-68 loss against the Blue Devils. “But everybody was saying, well, you’re going to put P.J. in for somebody else.

“Nobody knows my team. But it’s popular to say who the (heck’s) supposed to be in the lineup and you don’t know what the dickens you’re talking about.”

Whether Hairston should remain in UNC’s starting lineup is likely to remain a popular topic among those who follow Williams’ team. Hairston on Wednesday scored a game-high 23 points in a season-high 34 minutes.

He didn’t shoot well – and made just one of his seven 3-point attempts – but Hairston’s presence in UNC’s four-guard starting lineup seemed to energize the Tar Heels, who played with the kind of urgency and intensity that Williams has long sought.

Hairston said he learned earlier in the week that he would be starting at Duke. He didn’t have much of a reaction.

“It was just more of a, ‘OK, I’m ready,’ ” Hairston said.

He seemed to be. Prone to slow starts, UNC instead was at its best early at Cameron Indoor Stadium. The Tar Heels led by as many as 10 points in the first half before taking a 33-29 lead into halftime.

During the second half, when the Tar Heels went cold, Hairston remained their most consistent scorer. Sixteen of his 23 points came during the second half, when UNC attempted to stay in the game after Duke seized momentum thanks in part to its 3-point shooting.

Hairston’s presence in the starting lineup helped UNC in a variety of ways. For one, it made the Tar Heels a quicker team more suited to play at Williams’ preferred fast pace. Second, it made the Tar Heels more potent offensively. Hairston’s presence also created matchup problems for the Blue Devils’ defense.

“Knowing that they only post up one big guy kind of helped us go to that lineup,” said Marcus Paige, UNC’s freshman point guard. “And at the same time, making their (power forward) guard P.J. at the four is a great matchup for us 90 percent of the time. And it does give us more space.”

That additional space allowed Paige and Dexter Strickland more opportunities to penetrate. That, in turn, opened up the interior for James Michael McAdoo, the lone forward who started for UNC Wednesday night.

Hairston bolstered the Tar Heels’ offense and he wasn’t a liability on defense. Part of the reason why Hairston started, Williams said, is because Duke’s power forwards – whom Hairston had to guard when the Blue Devils played one of their usual lineups – aren’t known for their ability to score.

“Duke’s four-man (Amile Jefferson and Josh Hairston ) is not a focal point of their offense,” Williams said. “... So we hoped that P.J. would be able to battle and guard inside. He did fine with that.”

Williams used 20 lineup combinations during UNC’s 87-61 loss at Miami last Saturday. The Tar Heels’ starters played together for less than five minutes, and Williams seemed to be searching for the right combination of players.

He might have found it Wednesday night. UNC’s starters were on the court together for more than 17 minutes, and Williams used about half the lineup combinations at Duke as he did at Miami.

“I thought it was great,” said Dexter Strickland, UNC’s senior guardof Hairston starting. “He had seven (offensive) rebounds and enabled our team to run even faster, getting out on the break.”

It’s unclear whether Hairston will remain a starter. He started on Wednesday in place of Desmond Hubert, the sophomore center who providesdefense and rebounding. Offensively, Hubert has struggled. He played 1 minute at Duke, and has played more than 14 minutes in just two ACC games.

Still, Hubert provides UNC with an interior defensive presence that Hairston can’t replicate. But Hairston provides the Heels with scoring potential that most of his teammates can’t match.

“I got comfortable when we added P.J. in the lineup because he brings another scoring ability (and) offensive rebounding,” junior guard Reggie Bullock said. “He’s just another player out there that I feel comfortable playing with. And for coach to put him in the lineup and give us an extra shooter in the starting five, it was great.”

Whether it was permanent remains to be seen.

“Who knows,” Williams said when discussing his lineup. He joked that he might start five new players on Saturday when UNC hosts Virginia.

Carter: 919-829-8944 Twitter: @_andrewcarter