Brad Sneary led Saint Francis with 14 points and 12 rebounds while Scott Kohne added 13 points and blocked seven shots for the Cougars.
Seth Small chipped in eight points in the win, and and Ethan Hussey scored six points, dished out six assists and grabbed six rebounds.
Kohne also finished with seven rebounds to help the Cougars to a 27-19 advantage on the boards.
Spring Arbor got no closer than 11 points in the second half despite shooting 48 percent on 13-of-27 shooting.
Saint Francis led by as many as 17 points in the second half, 51-34 with eight minutes to play after a Sneary bucket inside.
The Cougars jumped out to a quick 9-0 lead with Sneary scoring inside to start the half. Saint Francis led by as many as 17 points, 29-12, and finished the half with a 31-18 advantage.
Sneary scored 10 points to lead the visiting Cougars, who connected on 13-of-30 shots for a .433 percentage.
Kohne blocked four Spring Arbor shots in the first half and the Cougars limited their opponent to .269 shooting (7 for 26).
Saint Francis also controlled a 23-15 rebounding advantage with Sneary grabbing seven to lead the board work.
The Cougars will host league foe Goshen on Saturday at 3 p.m.