Freshman Chase Plummer (Elizabeth, N.J./St. Patrick) and grad student post Justin Fry (New Bloomfield, Pa./West Perry) led UMBC with 9 points apiece.
UMBC got out to a 7-0 lead, but committed 13 first half turnovers and the hosts hit 14 of their final 19 shots in the final 15:17 of the half. Rider's run was 41-4 before settling for a 43-15 halftime advantage.
UMBC hit only 28.6 percent from the floor, making only 16 of 56 shots from the floor. Rider hit 27 of 46 shots from the floor (58.7 percent).
The Retrievers return home for the first time since Nov. 20 when they host Towson on Saturday at 7:00 p.m.