Will Barton added 15 points, while Witherspoon scored 12 and pulled down 11 boards for the Tigers (17-7, 7-2 Conference USA), who have won back-to-back games and five of six. That only loss in their recent slate of games came against Southern Miss on Feb. 1, the first-place team in the conference.
Memphis stayed in the thick of the conference race with a win in this one, though, getting ahead early in a close game. The Tigers never trailed after the opening minutes, led 37-25 at intermission and held on despite being outscored 34-33 by the Pirates in the second half.
Memphis outscored East Carolina 40-24 in the paint and got 21 points off 15 Pirates turnovers.
Miguel Paul finished with 13 points to pace the Pirates (12-11, 3-7).