Vandy guard Matthew Fisher-Davis led the Commodores (3-6) with 16.
MTSU out-rebounded Vandy 39-33.
The teams battled through a physical, closely-contested second half. Vandy led by six after forward Jeff Roberson hit a lay-up to start the half.
But the Blue Raiders bounced back to go up two after King's four-point possession that started when he missed a foul shot. MTSU (6-1) snagged an offensive board, then, King spun in the lane, dropped in a layup and added the ensuing free throw after he was fouled with 13:26 left.
It remained a one-basket game from there almost the entire rest of the night.
But with the shot clock about to expire with 1:15 left, MTSU's Potts drained a 3 from the left side with 1:15 left, putting MTSU up 66-60.
Vandy guard Riley LaChance hit three foul shots with 39 seconds left, and Potts missed a jumper.
That gave Vandy one final shot, but LaChance mis-fired on a long, off-balance 3 with two seconds left.
The Blue Raiders started the game 7 of 10 from the field--almost all on lay-ups and short jumpers--and led 15-8 on a King jumper with 13:43 left in the half.
But the Commodores soon caught fire, too. A Fisher-Davis 3 from the right side with 3:19 left gave Vandy its biggest lead of the half at 30-23, before settling in with a 32-28 lead at the break.
King led all scorers at the half with 15 points. The Blue Raiders cooled off their hot start and wound up shooting just 36.4 percent in the first half.