IPFW (16-5, 5-1 Summit) took the lead for good at 63-62 on Max Landis' basket with 6:02 left - part of a 10-0 run that pushed the Mastodons up 68-62 with 1:27 left.
Kory Brown's 3-point play 14 seconds later cut the deficit to three for the Bison (13-7, 3-3), but Joe Reed answered quickly with two points and IPFW maintained enough in the final minute to deny the Bison a chance to tie.
Max Landis had 17 points to lead the Mastondons. Joe Reed added 15 and DeAngelo Stewart scored 11. It was the freshman Koncher's third double-double in a row and his sixth of the season.