South Carolina (9-3) trailed only after the opening basket and won a season-high fourth straight despite missing three players from its lineup.
Senior guard LaShay Page missed his second straight game over an academic situation and freshman forward Michael Carrera missed the game with a left hip injury. Junior guard Bruce Ellington is with the football team in Tampa, Fla., preparing to play Michigan in the Outback Bowl on Tuesday.
Richardson scored 12 first-half points to help give the Gamecocks a 40-24 halftime lead. South Carolina shot 57.1 percent (16 of 28) in the first half, including 5-for-8 on 3-pointers. Richardson led the way with 4 of 5 from the field and 3 of 4 behind the 3-point arc.
The Gamecocks increased their lead to as many as 20 points in the second half and were up 52-32 with just under 13 minutes left before the Blue Hose (2-11) made a run behind Jordan Downing and Khalid Mutakabbir. A 17-7 run trimmed the deficit to nine points, 63-54 with 4:19 left, but South Carolina responded with 11 straight points.
The run started with a second technical foul on coach Greg Nibert after a foul call with 4:02 remaining. Richardson made both technical foul shots and 1 of 2 free throws on the call Nibert was arguing. Mindaugas Kacinas followed Richardson's missed free throw with a layup to push the lead back to 14 points before the Blue Hose had possession again.
Kacinas added 13 points for South Carolina and Lakeem Jackson chipped in 10 points. Downing led Presbyterian with 19 points before fouling out and Mutakabbir added 17.