Shawn Long added 22 points and 12 rebounds for the Ragin' Cajuns (7-3).
With Houston holding an eight-point first-half lead, the Ragin' Cajuns came back in the second to even the score at 45 with the help of back-to-back 3-pointers by Steven Wronkoski and Kevin Brown.
With three seconds left in the game and the Cougars leading by one, a Houston foul sent Payton to the line for two. He made the first, tying the game at 69, but missed the second, sending the game into overtime.
In OT, the Ragin' Cajuns opened with a 7-0 run to lead 77-76. With 12 seconds left, Payton again went to the line, this time sinking 2 of 2 for the win.
TaShawn Thomas scored 27 points for the Cougars (7-5).