Iona matched its largest lead at 66-51 with 6:50 to go after Marist (5-22, 4-13) led 35-34 at halftime.
Chauvaughn Lewis made 1 of 2 free throws to pull Marist back within three at 69-66 with 20.8 seconds left.
Lewis finished with 25 points and reached 2,000 career points on a driving layup with 3:23 left in the first half. He became the 12th member of the MAAC's 2,000-point club and the second at Marist. Lewis (2,013) needs 65 points to pass Steve Smith (1979-83, 2077) for the Marist record.
T.J. Curry added a career-high 17 for the Red Foxes.