Kennedy Meeks added 12 points and 14 rebounds, Joel Berry II scored seven of his 12 in the final 5 minutes and Marcus Paige hit four free throws in the final 10 seconds to help the Tar Heels (25-6, 14-4) earn their first win on Duke's floor since 2012.
North Carolina never trailed and rode its inside game, building a 64-29 rebounding advantage and outscoring Duke 42-20 in the paint.
Grayson Allen scored 29 points while Luke Kennard added 20 for the Blue Devils (22-9, 11-7), who hit 13 3-pointers — including one by Kennard with 9.3 seconds left that made it 72-70.
Paige hit two free throws with 8.8 seconds left. After Marshall Plumlee dunked home Allen's missed layup with 2.8 seconds left to make it 74-72, Paige iced it with two more foul shots with 1.5 seconds.
Justin Jackson added 13 points and Paige finished with 11 for the Tar Heels, who earned just their second victory at Cameron Indoor Stadium since the Tyler Hansborugh-Danny Green-led group went 4-for-4 here from 2006-09, and their first since 2012.
Duke escaped the Smith Center last month with a 74-73 win after the Tar Heels — who never could put the Blue Devils away in that one, and paid dearly for it — had a shot blocked on the game's final possession to end it.
For a while, it looked like North Carolina would decide Round 2 much earlier, twice pushing its lead into double figures in the opening half while completely owning the paint — holding a plus-20 rebounding margin at halftime and outscoring Duke 26-8 in the paint.
But the Tar Heels missed their first 11 shots of the second half against the 2-3 zone the Blue Devils ran to mitigate that interior disadvantage. That gave Duke a chance to come back, with the Blue Devils hitting 3s on four straight possessions.
Allen capped that burst with one from the key with 12 minutes to play that made it 49-all — the first tie since the opening tip.
North Carolina: The Tar Heels' rebounding total was a season high. ... Former stars Tyler Hansbrough and Marvin Williams, both now with the Charlotte Hornets, watched from behind the UNC bench.
North Carolina: ACC Tournament quarterfinal, March 10 in Washington.