The Bulls (2-5) closed out the first half on a 25-4 run, breaking open a tight game that was tied at 25 at the 8:55 mark.
The Division II Mountaineers (1-1), who defeated Roberts-Wesleyan 100-64 in their opener, could get no closer than 18 in the second half.
Buffalo had a 37-26 rebounding advantage and scored 26 points off 15 Mansfield turnovers. The Bulls shot 56.8 percent in the first half (21 of 37), but cooled off to 36 percent in the second (9 of 25).
Buffalo, off to its worst start since the 2000-01 season, tied the all-time series with Mansfield at 4-4 in their first matchup since 1989.