CHARLOTTE, N.C. -- Zion Williamson made the difference for fifth-ranked Duke in its third matchup with rival North Carolina.

Williamson tipped in his own miss to put the 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 semifinals.

The 6-foot-7, 285-pound freshman -- who barely played in one regular-season loss to UNC and not at all in the second -- finished with 31 points and 11 rebounds for the Blue Devils (28-5).

"He put on his Superman jersey," UNC coach Roy 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.

Cameron Johnson had 23 points for the Tar Heels (27-6), 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 three 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 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 that finally secured a ticket to the tournament final.

"I mean it was tough watching the first two (Duke-UNC) games, wishing I could go to war with them," said Williamson, who was hurt in the opening minute of the first meeting Feb. 20. "The rivalry lived up to what it was expected to be."

BIG PICTURE

Duke: This tournament has largely been about Williamson's return from the injury that had sidelined him for nearly six full games, and what it means for the Blue Devils going forward. He had 29 points on 13-for-13 shooting -- the best performance without a miss in the event's 66-year history -- in the quarterfinal win against Syracuse. Williamson had another big game, but the Blue Devils also got sparks from spot-duty reserves like Jordan Goldwire and Antonio Vrankovic while Javin DeLaurier's work on the boards kept Duke in it early as UNC was in full sprint by the opening tip. It was another sign that Duke, with Williamson back, is closer to being the version that spent a national-best seven weeks at No. 1 in the AP Top 25 this season.

UNC: The Tar Heels had claimed their first regular-season sweep of the Blue Devils since 2009, a year that ended with Roy Williams claiming his second NCAA championship. They were trying to beat Duke three times in a season for the first time since 1976, though Williamson barely played in the first game and not at all in the second due to a knee sprain. The Tar Heels proved they're on level footing with the Blue Devils with Williamson back, but couldn't figure out a way to close it out.

UP NEXT

Duke: The Blue Devils advanced to the championship game against 12th-ranked Florida State. The Seminoles upset No. 2 Virginia in the s first semifinal.

UNC: The Tar Heels are headed to the NCAA Tournament, though it's unclear whether they've done enough to secure a No. 1 seed.