Maurice Barrow added 11 points and Amadou Sidibe had 10 for Fairfield (14-10, 6-6), which won its fourth straight.
Tied 41-41 at the 10:30 mark, Fairfield took a double digit lead, 59-45, behind an 18-4 run capped by Desmond Wade’s layup with 2:34 remaining. Barrow sparked the run with consecutive baskets and scored nine points during the stretch.
Siena (6-17, 4-8) cut the lead to single digits, 60-51 with just 52 seconds left, but Fairfield made four consecutive free throws to ensure the win.
The Stags shot 46.4 percent (13 of 28) in the second half compared to the Saints’ 33.3 percent (10 of 30).
O.D. Anosike led the Saints with 15 points and eight rebounds.