Justin Bassey added 12 points and seven rebounds for Harvard (18-7, 7-3 Ivy League), which has won four in a row.
Consecutive buckets in the paint by Idan Tretout, Lewis and Justin Bassey helped the Crimson build a 57-51 lead with 8:21 remaining in the game. Harvard held the lead for the remainder of the game, going up 68-60 with 2:34 remaining.
Penn's Max Martz hit a 3-pointer on the ensuing possession and AJ Brodeur scored in the paint to draw the Quakers within 68-65 with 1:12 to go but a free throw by Bassey would be the only remaining point in the game.
The Crimson leveled the season series against the Quakers with the win. Penn defeated Harvard 75-72 on Jan. 31.
Harvard plays at Columbia on Friday. Penn plays at Yale on Friday.
For more AP college basketball coverage: https://apnews.com/Collegebasketball and http://twitter.com/AP-Top25
Elements of this story were generated by Automated Insights, http://www.automatedinsights.com/ap, using data from STATS LLC, https://www.stats.com
Joe Johnson makes scoring 35 points look easy
Former NBA All-Star Joe Johnson knocks down easy buckets for Overseas Elite as they move on to the semifinals of the TBT.
Iso Joe carves up Herd That, still has shooting touch
Former NBA All-Star Joe Johnson shows he can still score easily with this fadeaway jumper.
Pac-12 commissioner Larry Scott tests positive for coronavirus
Pac-12 commissioner Larry Scott is self-quarantining at the direction of his doctor and continuing to work remotely after testing positive for the coronavirus, the league announced Friday night.