Tied at 40, Seilund scored six straight points to spark a 10-1 run, giving the Knights a 50-41 lead with 11:50 remaining. Steve Glowiak hit a 3-pointer to pull Sacred Heart within four, 64-60 with 2:23 to play, but the Knights were 9 of 10 from the line to seal it.
Scooter Gillette scored 11 points and Mustafaa Jones and Matt MacDonald each scored 10 for Fairleigh Dickinson (10-17, 6-7 Northeast Conference), which has won two straight since snapping a five-game losing skid.
Louis Montes scored 19 points and De'von Barnett added a season-high 18 to lead Sacred Heart (4-24, 1-12), which has lost 11 straight games. Mostafa Abdel Latif grabbed 14 boards for the Pioneers.