The Hornets scored seven of the final nine goals to take down the Thunder 14-13 in overtime.
Tabs
Heeren did it on both sides of the field with 11 goals and an assist for 12 points, 21 draw controls, eight ground balls, and three caused turnovers.
Kalamazoo won 20-12 at Saint Mary's on Saturday.
Kalamazoo was defeated 18-8 by Albion at home on Tuesday.
The Hornets fell to the Flying Dutch 17-6.
Kalamazoo scored with 11 seconds left in the first overtime to win 16-15 at Calvin on Wednesday.