The Rams trailed by seven at the half, and were behind, 54-49 when swingman Ronnie Clark scored the Rams next six points to give the team a 55-54 lead with 13:54 remaining. The teams would exchange three more leads before center Matt Nelson's dunk with 10:26 to play gave the Rams a 59-58 lead.
Clark finished with a team-best 21 points, one of four Rams in double figures, as Dale Layer's squad moved to 9-2 on the year and won for the 10th game in a row at home, tying for the third longest streak in arena history.
Guard Andy Birley and reserve forward Matt Williams each scored 14 points, while Nelson finished with 10.
Layer said it was a game of contrasting halves. South Carolina shot 57 percent the first half and led by seven. The Rams outscored USC, 48-27 the final stanza and made 15-of-24 field goals, 63 percent.
"We challenged our guys at halftime. They (USC) came into Moby Arena, and took the fight to us in the first half," he said. "Defensively, we were much better in the second half. I thought we were much more aggressive in the second half. We didn't get the hustle rebounds in the first half."
Layer said beating an SEC team that defeated the Rams a year ago in Columbia was another step in his program's continued development.
"I think it's another step. I like the way our team is developing. We're much more balanced and we have much more depth," he said.
The win concludes the pre-Christmas part of CSU's slate. Players will return home for a brief holiday break before convening in Fort Collins Dec. 26 to resume practice. The Rams face Prairie View A&M Dec. 27 at 7 p.m. in Moby Arena in the team's next game.