UMBC slipped to 8-10 overall and 2-4 in America East play, while Boston improved to 9-9, 4-2.
UMBC led for much of the first overtime period, until Terrier reserve Jeff Pelage tossed up a wild shot inside and drew Retriever forward Chauncey Gilliam's fifth foul. Pelage's shot fell and he hit the ensuing free throw to tie the game at 70-all with 1:32 remaining.
Burrier scored UMBC's first four points of the second overtime, but missed a free throw when fouled on his second lay-up which left the game tied at 76-all with 1:42 remaining. BU's John Holland gave the hosts a 78-76 lead on two free throws with 1:36 remaining, but Retriever junior wing Matt Spadafora (Richboro, Pa.) drew a foul on a baseline drive with eight seconds remaining.
Proctor hit 11 of 19 shots from the floor and added three assists and two blocked shots in 50 minutes. Greene, who did not play at Vermont on Monday due to headaches after suffering a concussion vs. Hartford on Jan. 17, recorded 10 assists and just one turnover.
Spadafora, who tied the game at 61-all (for the first time since a 16-all tie) on a 3-pt. field goal with 1:11 remaining, scored 14 points and added five assists in 49 minutes. Fry added 10 points and a team-high nine caroms in 48 minutes, while Gilliam posted 14 points. Burrier, who hit his first career 3-pt. field goal in the first half, boosted the depleted Retrievers with seven points and three rebounds in 15 minutes of action.
UMBC got out to a solid start, leading 16-11 at the 12:21 mark of the first half. But the Retrievers stopped solving the Terrier zone, and Boston outscored UMBC, 28-6 to finish the half. The Retrievers hit 29 percent from the floor in the first 20 minutes, while the Terriers hit 14 of 24.
Each team attempted 22 free throws and UMBC missed nine, while Boston missed five.
The Retrievers finish their three-game road swing at Albany on Sunday.