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
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