The visiting Bucs won the OK-Red matchup, 48-45.
Grandville jumped out to a 9-7 lead after the first eight minutes of action.
Grand Haven came back with a 14-10 scoring advantage and took a 21-19 lead at the half.
The Grandville defense put the clamps on Grand Haven in the third period and outscored the Bucs, 12-3, to take a 31-24 going into the fourth quarter.
The Bucs eventually caught up to Grandville with a 15-8 fourth-quarter scoring advantage to tie things up at 39-all and force overtime.
Grand Haven secured the win by outscoring the Bulldogs 9-6 in overtime.
Grand Haven was led by Emersen Berndt, who led all scorers with 17 points. Gillian Sorrelle and Grace Harrison each had nine points and Heidi Berkey had seven and Maddie Schopf had six. Grace Harrison had four assists. Maddie Schopf had nine rebounds, while Berndt had four steals.
Grand Haven (7-3, 4-1) will travel to Hudsonville on Tuesday.