Baylor (20-1) rallied from a 15-point deficit in the first half to win its fifth straight game. The Bears trailed 50-40 early in the second half, but pushed ahead to take their first lead at 56-54 with 10:25 left after Motley made a pair of free throws.
It was a close game from that point forward. Lecomte hit a decisive 3-pointer with 23 seconds left that made it 78-72 and sent many of the Ole Miss fans to the exits.
The 5-foot-11 Lecomte shot 6 of 9 from the field, including 5 of 6 from 3-point range.
Ole Miss (12-9) dominated early on and jumped out to a 33-18 lead with 6:33 remaining in the first half. Sebastian Saiz and freshman Breein Tyree both scored 20 points for the Rebels. That was a career high for Tyree.