Xylina McDaniel scored 19 points and North Carolina held on to beat the Dukes 74-71 on Thursday.
Latifah Coleman added 14 points and Stephanie Mavunga had 10 points and 10 rebounds to help the Tar Heels (12-2) wrap up their nonconference schedule win their seventh straight.
Next up: A visit from No. 8 Maryland on Sunday in the conference opener.
With Hall of Fame coach Sylvia Hatchell watching from a high sideline platform, North Carolina shot 45.6 percent and let most of a 13-point lead disappear before coming up with the defensive stop they needed.
Hatchell has been out all season while she receives treatment for leukemia.
''I think they're very prepared,'' Calder said. ''Obviously, it was tough at the beginning with the Coach Hatchell situation, but they're playing for her and they're playing for themselves. ... The schedule has helped prepare us for the ACC.''
That includes the pesky Dukes (10-4), who trailed the entire second half but rallied to make the final minute interesting.
''We're probably about three possessions from being 13-1 right now,'' coach Kenny Brooks said of his James Madison team, which lost to Wright State by two points and to Vanderbilt in overtime.
Precious Hall finished with 18 points, Kirby Burkholder had 16 and Toia Giggetts had 14 points and 10 rebounds for the Dukes, who pulled within three points on Giggetts' layup with about 1:15 left.
UNC missed two 3-pointers - including one from Coleman that was blocked by Giggetts - before being called for a shot clock violation with 9.3 seconds left.
Angela Mickens took the inbounds pass and dumped it off for Burkholder, whose off-balance 3-pointer with 1 second left didn't draw iron. Giggetts missed a putback at the buzzer.
Brooks said Mickens ''gave up on the play'' and Burkholder was ''a decoy.''
''(Mickens) was supposed to dribble and go full-speed - almost do a jump-out-of-bounds pass,'' Brooks said. ''We really didn't get anything close to what we wanted.''
Allisha Gray added 11 points for North Carolina, which played without starting guard Diamond DeShields because of a left hand injury. DeShields, who averages 15 points, was in uniform but Calder said she ''was not going to play from the beginning'' but is expected to go against the Terrapins.
North Carolina hasn't scored fewer than 74 points since its 81-65 loss to then-No. 4 Tennessee on Nov. 11.
The Tar Heels were averaging more than 100 points during their last four games after reaching that mark three times during that span - including a school-record 124-point performance Dec. 16 against New Orleans.
This was their first game as a top-10 team this season after being off since beating High Point 103-71 on Dec. 21.
Things are about to pick up for North Carolina. After taking on Maryland, the Tar Heels will play host to rival North Carolina State (13-1) and then visit Florida State (12-1).
''It's kind of hard for me to argue that it's not the best (conference) in the country,'' Calder said of the ACC.