Nursing a 12-11 lead in the first half, the Roadrunners (6-9, 2-0 C-USA) pulled ahead with a 14-1 run sparked by a Jordan Sims 3-pointer and a three-point play by Hyjii Thomas. James Williams hit a 3-pointer, igniting a 16-5 run to open the second half and giving UTSA its largest lead, 54-33 at the 12:54 mark.
Charlotte (10-5, 1-1) looked to storm back with a run of their own as Denzel Ingram hit two straight 3-pointers to pull within eight. UTSA countered, pushing the lead back to 19 after a pair of free throws by McGregor.
UTSA shot 49.1 percent from the field. Williams finished with 11 points, while Thomas and Keon Lewis each had 10.
Ingram led the 49ers with 17 points and Terrence Williams contributed 15.