Princeton saw its 33-game Ivy League winning streak end with a 58-55 loss at Harvard on Friday night.
The Tigers (18-6, 9-1 Ivy) last loss in the conference was in 2011 to the Crimson as well. It was the fourth longest active conference winning streak, trailing Baylor, Delaware and Florida Gulf Coast.
Niveen Rasheed led Princeton with 13 points and 11 rebounds.
The Tigers, who lead Penn by one game in the Ivy standings, play Dartmouth on Saturday night. Princeton, which has won the last three conference titles, also had its 11-game overall winning streak end. The Ivy League has no postseason tournament so the regular season champion gets the automatic bid to the NCAA tournament.
Kristen Helmstetter scored 18 points to lead Harvard (16-8, 7-3).