The Seahawks (2-3) were trailing 55-47 when Marcus Burton hit a 3-pointer. Cooper took over from there, draining a 3-pointer, converting a three-point play and sinking the go-ahead layup with 1:43 remaining.
Burton split a pair of free throws, and Antonio Woods turned it over, leading to Senat's jumper that made it 62-58. Sam Jones hit a 3-pointer for Penn to make it 63-61 with 1.2 seconds left, and Burton hit 1 of 2 from the line after being fouled. Penn's inbound heave was tipped away as time expired.
Burton scored 17 points and Cooper had 15 for Wagner, which shook off an early 14-2 deficit.
The Quakers (0-5) shot 57.6 percent from the field, but had just two field goals in the final 10:18.