Cleveland State took permanent control with a 12-0 run in which Illinois-Chicago went scoreless for 5:53. Lee's 3-pointer ignited the surge, and Devon Long added five points.
Long's three-point play with 13:58 remaining gave the Vikings a 46-28 lead, and the Flames got no closer than seven points the rest of the way.
Mason was 8 of 12 from the field and added six rebounds. Lee finished with 10 assists.
NCAA title game hero Kris Jenkins said he will withdraw his name from the NBA draft and return to Villanova for his senior season.
Andy Katz breaks down the likelihood of Villanova, Syracuse, North Carolina or Oklahoma making a run to the Final Four next season.
Florida State has announced that Xavier Rathan-Mayes will return to the court for his junior season. The 6-foot-4 guard declared for the NBA draft last month but did not hire an agent.