Isaiah Williams added 21 points-5 for 10 from 3-and eight rebounds for the Gaels.
Iona (4-3) entered the game minus leading scorer A.J. English who injured his left hand prior to the Gaels' Dec. 8 loss at Tulsa. Starting guard Schadrac Casimir was also out as he missed his third-straight game due to a hamstring injury.
The Gaels never trailed.
Late in the game, however, a Derrick Griffin dunk trimmed Iona's lead to 72-69 with 4:18 to play. Jahaad Proctor hit two free throws for Iona to make it 74-69 before Griffin's 3-point play made it 74-72.
An Ibn Muhammad 3 pushed the lead to 77-72 with 2:21 left to seal the win.
Orlando Coleman scored 23 points in 28 minutes off the bench to lead Texas Southern (1-9).