Pankey was 6 of 9 from the floor and 10 of 14 from the line with nine rebounds. The Jaspers were 11 of 24 as a team beyond the arc.
Manhattan (9-10, 6-4 Metro Atlantic) used a 10-2 run early - including 3-pointers by Calvin Crawford and Zane Waterman - and the last five points of the half by Pankey to build a 40-33 lead at halftime.
Monmouth (11-10, 7-3) erased the deficit and took a 49-47 lead 6 1/2 minutes into the second half on Justin Robinson's 3-pointer.
Pankey's layup with 4:35 left broke a 58-all tie. He stole the ball on the ensuing possession, was fouled on a layup, and completed the three-point play to put the Jaspers up by five.
Deon Jones led Monmouth with 18 points and Robinson finished with 14.