Preston Ross scored 11 points and Brandon Boggs chipped in 10 for the Catamounts (5-9, 3-0), who are 3-0 in the league for the first time since the 2008-09 season. Sumler also had six assists, four steals and four rebounds. Western Carolina had lost three in a row, but two of the losses came to Georgetown (81-68) and Tennessee (66-52).
The Catamounts led 36-25 at halftime and the closest the Bulldogs got in the second half was six points twice, the last at 46-40 on Mike Groselle's layup with 8:36 to go.
The Catamounts won the turnover battle 16-9.
Mike Krzyzewski says he has good reason to be excited for next season thanks to a combination of Duke's incoming freshmen and a core of experienced upperclassmen.
Georgia guard Juwan Parker has been awarded a medical redshirt, leaving him with two years of eligibility, after missing the 2015-16 season with a partially torn Achilles tendon.
Forward Trevon Bluiett has withdrawn from consideration from the NBA draft and will return to Xavier for his junior season.