Winthrop trailed early but pulled ahead 27-26 on a free throw by Andre Smith and led 29-26 at halftime.
Presbyterian led 33-31 in the second half after William Truss scored seven straight points, but Winthrop pulled ahead with a 9-4 run. The Blue Hose clawed back to lead 56-53 after Josh Downing made two free throws with 2:27 left. Xavier Cooks pulled Winthrop within one, 56-55, with a layup, then Okeke scored the go-ahead dunk with 1:22 left on the next Eagles possession.
DeSean Murray led the Blue Hose (5-11, 1-2) with 24 and 13 rebounds and Truss had 15 points and 10 boards.