Amanze Egekeze scored a career-high 16 points, Craig Bradshaw and Nick Smith had 15 apiece, and Reece Chamberlain scored 11 with eight assists for Belmont (14-7, 6-2 Ohio Valley Conference), which never trailed.
Bradds opened with a layup and Belmont never looked back, pulling to a 45-35 halftime lead.
Bradds scored six of Belmont's eight points to open the second half, then Smith hit back-to-back 3-pointers for a 59-41 lead and the Bruins continued to pull away.
Smith hit 5 of 7 from distance and the Bruins shot 70.8 percent from 3-point range and 53.3 percent from the field.
Avery Moore led the Gamecocks with 20, including six 3-pointers, Darion Rackley had 17 and JaQuail Townser 15.