JaMarcus Weatherspoon knocked down a pair of free throws and then hit a jumper to pull the Bobcats within three, 56-53, with 7:04 remaining. McClanahan and Gainey answered with back-to-back jumpers, sparking an 8-1 run that Texas State could not overcome.
UT-Arlington (14-9, 8-5 Sun Belt) held a 31-28 lead at the half and scored eight straight points early in the second to go up by 12 with 16:08 left to play.
McClanahan finished with 18 points and six assists, and Gainey had 15 points on 7-of-10 shooting. Drew Charles chipped in 12 points.
Emani Gant, Wesley Davis and Weatherspoon all finished with 12 points apiece for the Bobcats (11-12, 5-9), who shot just 33.3 percent (20 of 60) overall.