Bell had 13 points in the first half when the Blue Hose (9-13, 2-7 Big South Conference) shot 54 percent and opened a 33-26 lead. Dillard had 12 in the second half when Presbyterian held the Buccaneers (7-13, 2-7) to 27 percent shooting.
Phlandrous Fleming and Christian Keeling scored 13 points apiece for Charleston Southern, which stayed within striking range because Presbyterian went 5 of 10 from the foul line in the second half and committed 12 of its 19 turnovers.
Charleston Southern scored the first 10 points of the game but the Blue Hose caught up with their own 10-0 run midway through the first half and took the lead for good and scored the last eight points of the first half.
Mannion, who recently reclassified and is ESPN's No.11 overall player in the class of 2019, chose Arizona over Marquette.
He'll fit in with Sean Miller's plans for a faster tempo on offense.
The cream of the crop of American high school basketball will congregate in Colorado Springs from Oct. 5-7, as USA Basketball unveils its newly expanded Junior National Team minicamp in collaboration with the NBA, NCAA and NBPA.