Ogunyemi was 7 of 11 from the floor, 9 of 10 from the line and grabbed 11 rebounds. Brett Bisping added 20 points for the Saints (9-5, 2-1 Metro Atlantic), and Lavon Long had 12 points, nine boards and six assists. Siena won the rebound battle 37-21.
Niagara closed the first half with a 7-2 spurt and led at halftime 34-30.
Siena quickly erased the deficit in the second half, and Oqunyemi's jumper with 4:34 left put the Saints up by nine.
Cameron Fowler's 3-pointer with 2:43 left pulled Niagara within six, but the Purple Eagles got no closer.