In a poor-shooting night all-around, neither team shot better than 37 percent from the floor, nor made two-thirds of their free throws. The teams were a combined 5 of 29 from beyond the arc.
Zedric Sadler's 3-pointer with 6:31 in the first half lifted Rider (14-8, 8-3 Metro Atlantic) to an eight-point lead. But St. Peter's went on an 11-2 run and trailed by just two, 25-23, at the break.
Khalil Alford's layup with 5:46 left put Rider up by six. St. Peter's pulled to within one at 49-48 with 2:11 left on a pair of Dominique Marvin free throws, but Rider made six consecutive free throws inside of 52 seconds to ice it.
Welton Quadir paced St. Peter's (10-12, 4-7) with 15 points and nine boards.