Moore hit a 3-pointer to open the extra period for the Eagles (6-6, 1-0) and sank two free throws to make it 72-67. Shaquille Johnson answered with a three-point play for Longwood (4-10, 0-1), but Andre Smith followed with a 3-pointer and Xavier Cooks nailed a layup for a 77-70 lead with 1:12 remaining.
Smith finished with 14 points, Cooks had 13 and Joseph Lopez 12 for Winthrop.
Lotanna Nwogbo paced the Lancers with 18 points and 12 rebounds before fouling out and Shaquille Johnson also had 18 points. Longwood erased a late 12-point second-half deficit as Quincy Taylor hit two free throws and Shaquille Johnson blocked Keon Johnson's layup attempt in the final seconds to force overtime.