Kon Knueppel scored 17 points and No. 1 Duke held off a furious second half rally by North Carolina to beat its rival for the third time this season, 74-71 on Friday night to reach the Atlantic Coast Conference Tournament championship game.

There was a development in the ACC Tournament on Thursday that could have ramifications at both ends of the bracket. Duke All-American freshman Cooper Flagg suffered a sprained ankle in the first half of the Blue Devils' win over Georgia Tech in the ACC quarterfinals.

Duke freshman Cooper Flagg appeared to injure his left ankle after slipping under the basket and was helped to the locker room by two teammates late in the first half. He did not return.