Earl Pettis added 18 points and Sam Mills 12 for the Explorers (13-4), who haven’t dropped a contest since a 70-66 loss at Delaware on Dec. 19.
The Explorers got out to an early advantage, led 39-29 at the break and outscored the Quakers 29-28 in the second half to clinch it.
La Salle had a 33-31 edge on the boards, including a game-high nine by Jerrell Wright, but turned the ball over 16 times to 14 by Penn. Still, the Explorers had the edge in shooting, going 22 of 47 from the floor (46.8 percent) compared to just a 19 of 56 performance (33.9 percent) by the Quakers.
Fran Dougherty led the Quakers (7-9) with 14 points.