CHARLOTTE, N.C. — Zion Williamson didn’t hesitate when he saw his shot for the lead coming off the rim late in a tense game with Duke’s fierce rival. He bounced right back up in traffic for the kind of play that only he can make with his athleticism and size.

Yes, the Blue Devils’ freshman star now has his delayed big moment against North Carolina.

Williamson tipped in his own miss to put the fifth-ranked Blue Devils ahead for good, and Duke survived a final-play shot to beat the third-ranked Tar Heels 74-73 on Friday night in the Atlantic Coast Conference Tournament semifinals.

“That is just my competitive spirit,” Williamson said of the tip-in. “So when I saw it miss, my instinct was to get the rebound and go back up, but I realized I could just tip it in. It went my way.”

Williamson — who barely played in one regular-season loss to UNC and not at all in the second because of a knee sprain — finished with 31 points and 11 rebounds in his second game back for the Blue Devils (28-5). And it came with Duke facing the prospect of losing three times in a season to UNC (27-6) for the first time in 43 years.

“You don’t want to lose to a team three times in a row,” Williamson said. “You just want to win.”

Williamson has been the talk of college basketball all year with his high-flying dunks and athleticism in a nimble 6-foot-7, 285-pound frame. He came through in a huge moment Friday, prompting UNC coach Roy Williams to say Williamson “put on his Superman jersey again and was incredible.”

“It’s such a blend of strength and power and quickness that we couldn’t stop him getting the ball inside and going to the basket,” Williams said.

That last tip-in helped Duke survive a classic that went down to the final play.

After freshman RJ Barrett missed two free throws with 12.4 seconds left, UNC pushed downcourt for a final possession. Coby White launched a contested long jumper against Tre Jones, but the ball bounced out as Nassir Little crashed the glass for a tip attempt as the horn sounded.

That sent Duke’s bench into celebration and leaving a disappointed White crouching at midcourt in an arena filled with a buzzing instate crowd.

“I mean, it exceeded my expectations,” Williamson said of getting his first full-game taste of the rivalry. “The crowd was into it, it was a back and forth game. What could be better?”

Cameron Johnson had 23 points for the Tar Heels, but he also missed a stepback 3-pointer for the lead that set up Barrett’s missed free throws.

North Carolina led by 13 in the first half and 71-67 with less than 3 minutes left but couldn’t hold on. The Tar Heels also went ahead 73-72 on Little’s dunk with 48 seconds left, only to see Williamson respond by tipping in his own miss in the paint — battling through a crowd of white jerseys — to go back in front.

The Tar Heels shot just 40 percent, including 4 of 27 from 3-point range, against Duke’s aggressive defense that played tough after UNC landed an early flurry for the lead.

Barrett finished with 15 points, eight rebounds and seven assists in a matchup of two heavyweights contending for top seeds in the NCAA Tournament. They both looked the part, too — down to Duke’s final punch to advance.

“These two guys have an amazing will to win,” Duke coach Mike Krzyzewski said of Williamson and Barrett, “and it makes us coaches look a lot better.”