Muo was one of five players in double figures for the Buccaneers (7-6, 2-0), who have now won six of their last seven games. He got help from Paul Gombwer (13 points), Arlon Harper (12), Cedrick Bowen (11) and Jeremy Sexton (10).
Saah Nimley dished out 10 assists for the Buccaneers.
Winthrop (6-8, 0-2) overcame a 35-27 halftime deficit to take a 45-43 lead with 13:32 left to play. But Charleston Southern went on an 11-1 run to open it back up for good.
The Buccaneers had a decisive 24-11 advantage in bench scoring.
Gideon Gamble led the Eagles in scoring with 13 points. Larry Brown added 12 and James Bourne chipped in 11 more.