Iowa State finished the non-conference schedule with four straight wins and a 10-3 record.
Tennessee State kept the game close throughout the second half, coming back from an 11-point halftime deficit to pull within three before Clarks final basket from behind the 3-point line.
The Tigers built a quick lead, scoring the games first 10 points before giving up a 12-0 run. Iowa State ended the first half on a 20-10 run for a 34-23 lead.
Clarence Matthews led Tennessee State (2-5) with 14 points and Kareem Grant added 12. The Tigers were without leading scorer Bruce Price, who will miss the remainder of the season after tearing his ACL in a loss to Ohio State on Friday. Price was averaging 19.3 points.