With Tankelewicz knocking down four 3-pointers, the Catamounts (9-8, 2-0 Southern Conference) got 22 points off the bench to just five for the Phoenix (7-8, 0-1).
Western Carolina led 32-30 at halftime but a Koch 3 and a layup by Hamilton put the Phoenix up 39-38. The Catamounts regained the lead on a Tawaski King layup and Sinclair followed with a dunk he turned into a three-point play.
The Catamounts put it away with a 15-2 run for a 68-51 lead. Brandon Boggs capped the surge at 5:57 with a dunk.