Army built a 39-27 advantage at halftime and went on a 19-6 run midway through the second to go ahead 77-52.
Tanner Omlid added 14 points with two breakaway dunks and six steals for the Black Knights (5-7) which shot 54.4 percent from the field and 45 percent from 3-point range.
Lafayette led 15-11 in the first half before allowing Army to take the lead for good with nine straight points. The Leopards closed to within 20-19, but Army took a commanding lead after a 12-2 run and never allowed the Leopards to get back within striking distance.
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Forward Trevon Bluiett has withdrawn from consideration from the NBA draft and will return to Xavier for his junior season.