Louisiana-Monroe had an 11-point lead when Texas State used a 21-10 surge to tie the game at 50 with 5:16 left. Ongwae scored five straight points to make it 55-50. The teams traded buckets, and Wesley Davis hit 3 to pull Texas State within 57-55 with 2:21 remaining.
Majok Deng forced a turnover on an inbounds pass, and then split a pair of free throws to seal it for the Warhawks.
Marvin Williams scored 18 points to lead Louisiana-Monroe (9-6, 3-1 Sun Belt).
Gant had 14 points and Ethan Montalvo chipped in 12 for Texas State (9-5, 3-2).