CHAPEL HILL After one particularly painful loss, one of too many he had endured up to that point, North Carolina coach Roy Williams scoffed at the notion that a defeat might help his team – that it could be a learning experience.

Learning experiences, Williams said after a 91-83 loss at N.C. State on Jan. 26, were “for babies.” Still, whether Williams wanted to admit it or not, that loss – in addition to ones against Butler, Indiana, Texas, Virginia and Miami – helped fortify the Tar Heels.

Entering their ACC tournament quarterfinal Friday night, the Tar Heels believe they are a stronger team than they were in November and December. And one reason is they made it through those difficult early-season experiences and played their best toward the end of the regular season.

At least UNC had been before a deflating 69-53 loss against Duke last Saturday. How the Tar Heels respond will determine whether their stay in Greensboro is short or long, and whether they have one more run in them.

“I’m happy for our team and what they accomplished, especially after a tough early-season start, getting the third seed (in the tournament),” Williams said earlier this week. “I’m glad we bounced back like that. ... I am pleased with how they bounced back after some difficult times. That’s what we have to do right now.”

Amid defeats that called into question UNC’s potential and direction, Williams switched lineups after a 26-point loss at Miami on Feb. 9. Williams went to a four-guard starting lineup, with the 6-foot-5 P.J. Hairston at power forward.

UNC’s new look debuted at Duke a few days later. The Tar Heels lost 73-68, but played well and left Cameron Indoor Stadium with renewed confidence and belief. Then they won their next six games, and had their longest winning streak of the season going when Duke came to the Smith Center.

The Blue Devils’ 69-53 victory humbled the Tar Heels like some of those early games. In the 3 minutes, 26 seconds it took Duke to race to a 14-0 lead, UNC’s momentum – constructed over three weeks and six victories – had evaporated.

Williams is hoping his team’s confidence hasn’t, though he acknowledges the thought worries him.

Yet his team has learned. And those defeats, his players believe now, were beneficial.

“We’re just more mentally tough,” Hairston said. “Because a few months ago, Indiana, Butler and Miami even, at Miami, was sort of like we just kind of gave in (before) the last few minutes of the game.”

The Tar Heels did plenty wrong Saturday against Duke but quitting wasn’t one of them.

Williams didn’t meet with his players on Sunday – probably a good thing, he said later – but when he saw them Monday he told them they had reverted back to how they played during some of their blowout losses.

“Earlier in the season, we didn’t really have an identity as a team,” Paige said earlier this week. “So we had guys trying to do too much at times – especially when other teams would go on runs. But we know who we are. We just got away from that last game.”

The Tar Heels have responded well before, and believe they can again after one of their most disappointing defeats of the season.