Peters has scored in double figures in 21 of 22 games this season.
David Skara and Shane Hammink scored 10 apiece for Valparaiso (18-4, 8-1 Horizon League). Vashil Fernandez had eight points, eight rebounds and five blocked shots and Keith Carter added seven points, five rebounds and seven assists.
Kenny Carpenter's layup 36 seconds in gave Cleveland State (7-15, 2-7) a 2-0 lead but the Vikings went without a field goal for nearly six minutes as Valparaiso built a 10-3 lead.
Demonte Flanningan made a layup to cut Cleveland State's deficit to two points midway through the half, but the Crusaders made six 3s in the next 10 minutes and led 36-23 at the break.
The Vikings trailed by double figures the rest of the way.
Rob Edwards led Cleveland State with 13 points.