Adonis Filer scored 10 points and Milton Jennings added nine for Clemson (4-1).
Marist (2-4) got 15 points from Devin Price.
Both teams had split their first two games in the tourney.
Clemson used a 12-0 run to go up 44-32. Damarcus Harrison had five points, including a 3-pointer, during the surge. A slam by Booker extended the Tigers' lead to 48-34 with seven minutes to play.
Isaiah Morton had a 3-pointer and layup as Marist scored seven straight points to open the second half and take a 28-22 lead.
Marist shot just 34 percent from the field. Clemson outrebounded the Red Foxes 40-26.
Behind eight points by K.J. McDaniels, Clemson led 22-21 at halftime.
The Tigers beat UTEP 69-48 and lost to No. 17 Gonzaga 57-49 at the tournament. Marist lost to West Virginia and beat Vanderbilt.