The set scores were 27-25, 25-21 and 25-21.
Senior Taylor Wilkinson led Pentwater in the winning effort with a team-high 17 kills, while Terra Cluchey had 57 digs. Wilkinson also served a team-high three aces.
Allison McGregor had 32 assists for the Falcons.
Pentwater will play the winner of the Manistee Catholic/Walkerville matchup in the district finals Thursday night at 7 p.m.