Zimmerman closed its best-ever regular season with a 25-17, 25-21, 25-22 conquest of Milaca at home on Tuesday evening.
The Thunder will take an 18-7 record into the playoffs. They finished 9-3 in the Granite Ridge Conference for third place among nine teams.
Milaca dropped to 2-10 in conference and 6-17 overall.
Brooke Borchardt, 6-foot-1 junior, led the attack with 13 kiils, 5 blocks, and 2 aces. Nikki O’Keefe made 8 kills and 13 digs, Amber Magnuson 5 kills and 5 blocks, and Amanda Meleen 29 assists.
The Thunder will open Section 5AA on Thursday, Oct. 25, against a foe to be determined.