Stephen F. Austin (27-2, 16-0) went on an 11-0 run midway through the first half—fueled by Haymon's 3-pointer—en route to a 41-31 lead at the break.
The Lumberjacks turned a seven-point second half lead into 21 in the space of 2:20 as four treys by Walker opened the floodgates.
Jacob Parker had 13 points for the Lumberjacks, while Thomas Walkup added 11. Nikola Gajic gathered 10 rebounds, five on the offensive glass.
Antonio Benton paced SE Louisiana (11-16, 6-10) with 18 points. Jeffery Ricard had 12 points and eight boards and Onochie Ochie chipped in with 11 points.