The Bucs led 37-22 at halftime before the Sailors roared back and outscored them 15-4 in the third quarter.
The two teams each scored 15 in the fourth and Grand Haven’s win was preserved.
Zac Holman led Grand Haven with 17 points while Ross Koella scored 10.
Leading Mona Shores was Deandre Oakes-Owens with 17 points and seven rebounds. Kobe Burse added 14 points for the Sailors.