The teams traded 3-pointers at the end of the first half with Fleming making one and Liam O'Reilly scoring one for Gardner-Webb (10-11, 5-3) which went to intermission down 31-30.
Charleston Southern started the second half with a 7-0 run and later pushed the lead to 52-40 when Keeling hit a 3 then followed with a jumper with 13:44 left. The Bulldogs responded with a quick 7-0 spurt, but went more than four minutes without scoring as the Buccaneers went on a 12-0 run and Gardner-Webb never recovered.
James is the highest-ranked prospect to commit to the Vols under Rick Barnes and the highest overall since Tobias Harris in 2010.
Five-star point guard Josiah James, ranked No. 20 in the ESPN 100, has committed to Tennessee over Clemson, Duke and Michigan State.
Jim Calhoun, who has a career record of 873-380 and led UConn to three national titles before retiring in 2012, has been hired as coach at Saint Joseph.