Nelson hit a 10-foot bank shot with 24.3 seconds remaining to put Gardner-Webb (8-10, 1-2 Big South) ahead 54-49. Keon Moore responded with a basket with 14 seconds to again close the gap to three, but Josh Castellanos made a pair of free throws with 12.3 seconds left for the final margin.
Moore scored 20 points and James Bourne 10 for the Eagles (8-7, 2-1). Winthrop, which made 15 3-pointers in its previous game, a victory over Charleston Southern, made only 4 of 20 from long range on Wednesday. The Eagles shot 27.8 percent and missed 10 of their 27 free-throw attempts.
The victory was the first at Winthrop Coliseum for the Runnin' Bulldogs since its first season in the Big South in 2008-09.
ESPN's Dan Dakich joins The Paul Finebaum Show to discuss the SEC's presence in the NBA Draft.
Ted Kapita was the top-rated recruit from West Virginia in the class of 2015 and recently played at DME Academy in Florida.
With the Suns drafting Tyler Ulis, they now have five guards on their roster who attended Kentucky.