The Broncs (11-15, 8-6 Metro Atlantic Athletic Conference) have won two straight and five of their last six.
Trailing 59-49 with 7:19 remaining, Rider used a 15-4 run, including six points by Gadson, to take its first lead, 64-63, with 1:38 remaining. Brandon Penn scored on a layup with 45 seconds left and Gadson then hit three free throws with 18 seconds to go for a six-point lead.
A 3-pointer by Franklin Milian with 11 seconds left was the only field goal by the Golden Griffins (4-20, 1-13) in the final 5:24.
Penn had 12 points and 10 rebounds, Anthony Myles added 12 points and Jonathan Thompson had 10 of Rider’s 20 assists.
Harold Washington’s 15 points and 10 rebounds led Canisius, which has lost eight straight.