John Brisco led Prairie View with 20 points.
Prairie View was awarded two free throws on a technical foul called after a fan ran onto the court during a timeout with TSU holding a five-point lead in the final minute of the first overtime. After Prairie View made both free throws, Brisco hit a 3-pointer at the buzzer to send the game into the second overtime tied at 70.
Texas Southern outscored Prairie View 10-6 in the third overtime.
Texas Southern (6-9, 2-1 Southwestern Athletic Conference) has won three straight, and seven of the last eight over Prairie View (3-12, 1-2).
Prairie View played in its second straight overtime game, having defeated Alcorn State 70-67 Monday night.