Tyler Bernardini also had 19 points as the Quakers (3-1) spoiled the return for Robert Morris’ coach Andrew Toole. Toole played for the Quakers from 2001-03, helping them win two Ivy League titles.
The Colonials (2-1) shot just 35.7 percent (20 of 56) against Penn, and struggled from the foul line, going 13 of 22 (59.1 percent).
Robert Morris outscored the Quakers 22-14 in the paint, but was just 7 of 21 from behind the 3-point arc.
Miles Cartwright added 12 points for the Quakers, who shot 51.2 percent from the field (22 of 43), behind a 7-of-12 performance by Rosen.
Velton Jones led four Robert Morris players in double figures with 16 points. Caron Williams and Russell Johnson chipped in 13 points each and Lijah Thompson added 10.