Johnson came off the bench to put in 14 points and McAdoo provided 13, seven rebounds, three steals and two blocks for the Tar Heels (6-2).
Marcus Paige (12 points, eight assists), Kennedy Meeks (12, eight rebounds) and Nate Britt (11 points) also reached double figures.
Kyle Cain and Kayel Lock each scored 13 points to lead UNCG (4-5).
Cain also snared eight rebounds.
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