Coast Union lost 25-20, 18-25, 25-22, 25-17 to Dunn in a non-league match on Thursday.
Janelle Bohey had 10 aces and seven kills and Xue DiMaggio added five kills and three blocks.
Reagan Kniffen recorded five kills for the Broncos (13-4), who expects to be seeded Sunday for the Southern Section playoffs and will likely either have a bye or a home game on Tuesday.
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