Stony Brook sophomore guard Bryan Dougher tied Gilliam, UMBC's America East Player of the Game for the second consecutive game, for game-high scoring honors with 23 points, while senior wing Muhammad El-Amin added 20 points.
The Seawolves jumped out to a 20-4 lead at the 13:29 mark of the first half and still led, 36-23, with 5:39 to play. But Gilliam scored ten of his team-high 13 first half points and Jackson added the other five as the Retrievers outscored the Seawolves, 15-8 in the final 5:18 to trail by only 44-38 at intermission.
The Retrievers hit 12 of 24 shots from the floor and six of 12 from behind the arc in the first 20 minutes.
UMBC cut the deficit to 50-45 early in the second half, but a 7-0 Stony Brook run restored a double-digit lead. The Retrievers would whittle the lead down to six points at 68-62 on a Matt Spadafora (Richboro, Pa.) jumper with 2:55 remaining.
The Seawolves misfired on their next possession, and sophomore guard Chris De La Rosa (Washington Heights, N.Y.) came down on a fast break, but his driving layup was blocked by SBU's Tommy Brenton. El-Amin converted a short jumper and free throw with 1:49 remaining to end UMBC's comeback effort.
UMBC's rebounding woes continued, as Stony Brook collected 25 offensive caroms and outrebounded the Retrievers, 50-28. Stony Brook had 15 second-chance points, compared to four for UMBC.
Freshman wing Shawn Grant was UMBC's other player in double figures with 11 points, but he did not score in the second half. De La Rosa had an outstanding floor game with seven assists and no turnovers in 30 minutes of action.
Gilliam scored 20 or more points in two straight games for the first time in his career, after tallying 21 at Albany on Saturday.
The series stands at 8-8, and Stony Brook has won the last three contests.
UMBC returns home to open a three-game homestand vs. New Hampshire on Thursday.