The back-and-forth battle before a crowd of 555 saw 29 ties and 12 lead changes.
Kaity Weimerskirch helped the Redbirds prevail with 18 digs. Sarah Kushner added 15 digs. Allie Otten contributed a dozen while also dishing out a team-high 27 assists. Carley Nicholson had 24 assists.
ISU dominated statistically with a 60-38 advantage over the Crusaders in kills and led in digs, 73-51. Valparaiso fell to 8-14 overall and 3-5 in the Valley.
The Redbirds begin the second half of the Valley campaign on Friday at Southern Illinois before traveling to Missouri State for a conference game on Saturday.