The Bison (10-3, 3-1 Summit) scored 14 straight points to break away from a 54-54 game with 9:01 to play. Alexander was 14 of 16 from the free-throw line, where North Dakota State made 33 of 42, both team season highs.
Mike Felt scored 14 points, including all three of the Bison’s 3-pointers.
Frank Gaines scored 26 points to lead the Mastodons (7-6, 1-3). Justin Jordan added 14 points and Trey McCorkle scored 10 for IPFW, which was scoreless for 6 minutes in the NDSU run.