Ahead at halftime 35-32, Cleveland State started the second half on a 21-7 run to break open the game and take a 56-39 lead with 13 minutes left to play. Mason, Kamczyc and Lee each hit 3-pointers during the run.
Cleveland State shot 57.7 percent (15 for 26) in the second half while holding the Redmen to 32.3 percent (10 for 31).
The Vikings outscored Rio Grande 12-2 on fast-break points in the second period.
Dominick Haynes led the Redmen (4-10) with 17 points.