Smith also handed off 10 assists while Kyle Singler and Seth Curry each added 11 points for the Blue Devils (30-4), who downed their intrastate rivals en route to a third straight conference crown.
Miles Plumlee contributed nine points and seven rebounds as Duke took its 19th all-time conference championship and reached the 30-win mark for the third consecutive year.
The Tar Heels (26-7) got 16 points from Harrison Barnes while John Henson added 10 and a game-best 18 rebounds.
North Carolina hasn't beaten Duke for an ACC Tournament crown since 1998.
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