With it tied at 65 with 8:06 to play, the Vikings (22-5, 11-4 Horizon League) scored five straight. Youngstown State (8-17, 2-13) then cut it to 70-68 on Ashen Ward's 3-pointer with 6:14 left, but wouldn't get any closer as Cleveland State answered with a 15-4 run.
Trevon Harmon capped the spurt to give the Vikings a 13-point lead, 85-72, with 45 seconds remaining.
Harmon finished with 17 points, and Aaron Pogue and Jeremy Montgomery added 10 points each for Cleveland State.
The Vikings shot 47.4 percent from the field (27 of 57) in their fifth straight win against Youngstown State.
Damian Eargle scored 22 points and Ward finished with 15 for the Penguins, who lost their third straight.