Winthrop (17-12, 10-6) won 10 conference games for the first time since 2009-10.
Keon Moore added 11 and Keon Johnson 10 for the Eagles, who will be the No. 4 seed from the South Division for the conference tournament that begins Wednesday in Myrtle Beach, S.C. Presbyterian (6-25, 2-14) will be the No. 6 seed from the South.
Josh Downing scored 34 points for the Blue Hose, three points shy of his career high of 37 set earlier this season. Reggie Dillard added 12 points.
The Eagles shot 49.1 percent overall and made 11 of 20 3-point tries (55 percent), including 4 of 5 by Farmer.
Winthrop led by double digits from 17:27 of the second half.