Craig Bradshaw, who led Belmont with 28 points, missed a contested jumper at the buzzer.
Belmont led 43-29 at halftime but went without a field goal for 10 minutes in the second half. The Eagles went on a 15-0 run, taking a 61-59 lead on a layup by Elechi.
Bradshaw tied it at 75 at 1:07, was fouled and missed the free throw but Elechi stumbled out of bounds with the rebound. On the inbounds, Bradshaw broke free to score.
After an Arrington free throw, Bradshaw missed a 3 and Elechi was fouled rebounding an Arrington miss.
DeJuan Marrero had a career-high 21 points and 11 rebounds for the Eagles (14-11, 8-5), who lost by six at Belmont nine days earlier.