The Spartans (11-12, 4-4 Southern Conference) trailed by 18 early in the second half, but stormed back as Potts drilled six 3-pointers to fuel a 33-14 surge and push into the lead, 56-55.
Ty Toney scored to pull within three, but the Mountaineers couldn't connect on a 3-pointer during the ensuing possession. Potts hit two free throws for the final margin.
Potts finished 8 of 13 from beyond the arc and Tevon Saddler added 10 points with seven boards.
Tommy Spagnolo led Appalachian State with 15 points and 17 rebounds.