CHARLOTTE - Kon Knueppel scored 17 points and No. 1 Duke, playing without star freshman Cooper Flagg, held on after building a 24-point lead, beating North Carolina 74-71 in the Atlantic Coast Conference tournament semifinals on Friday night.

North Carolina botched a late free-throw situation that could have given it the lead.

Duke's Khaman Maluach had 13 points and nine rebounds before fouling out and Sion James added 12 points. Patrick Ngongba II's season-high 12 points off the bench were also a boost for the Blue Devils.

Flagg missed his first game of the season after suffering a sprained ankle in the first half of Thursday's quarterfinal win against Georgia Tech.

Top-seeded Duke (30-3) meets either No. 10 Clemson, the third seed, or No. 13 Louisville, the second seed, in Saturday night's championship.

Ven-Allen Lubin poured in 20 points and Elliot Cadeau had 15 for fifth-seeded North Carolina (22-12), which lost for the second time in its last 10 games. Both defeats have come to Duke.

The Blue Devils have won all three meetings against North Carolina this season, including two in a seven-night span.

North Carolina, playing its third game in three days after beating Notre Dame and Wake Forest, trimmed a 24-point deficit to 56-44 with more than 11 1/2 minutes remaining.

Duke's lead stood at 70-64 when it called a timeout with more than four minutes to play. Then Cadeau's basket brought the Tar Heels within 72-68.

Drake Powell made a free throw, then missed a would-be tying 3-pointer with about one minute remaining. Seth Trimble's two free throws at the 32.2-second mark closed the gap to 72-71.

Duke's Tyrese Proctor then missed the front end of a 1-and-1 with 21.7 seconds remaining. But Lubin missed a potential tying free throw, then the Tar Heels committed a lane violation to negate his second attempt with 4.1 seconds left.

Knueppel sank two free throws with 2.8 seconds on the clock.

Duke, buoyed by a 15-0 run to end the first half, held a 45-24 halftime lead. North Carolina failed to score on its final eight possessions.

Duke jumped out to a 27-17 lead as the Tar Heels went 0-for-7 on 3-point attempts.

Knueppel's third 3-point basket in three attempts helped the Blue Devils to a 30-21 edge.

By halftime, North Carolina was 1-for-10 on 3-pointers.

Duke was also without reserve forward Maliq Brown (shoulder).

--Bob Sutton, Field Level Media