Saturday's win marked the second straight weekend in which Penn (13-11, 5-2 Ivy League) followed a Friday loss with a victory on the following night.
Given how much energy the Quakers expended against Harvard on Friday, it was not surprising that Penn began somewhat sluggish against the Big Green. Dartmouth (4-20, 0-8) held a 12-7 lead just over eight minutes into the first half.
"It's easy to make excuses about our schedule, playing back-to-back, and Friday night's game," Allen said. "For us to come out and perform the way we did today is disheartening."
Penn eventually found its legs on both offense and defense, and controlled most of the rest of the half. A fastbreak layup by Miles Cartwright just before the buzzer gave Penn a 27-22 lead at intermission.
Although Penn jumped out to a 38-26 lead early in the second half, Dartmouth came back and tied the score at 48-all with 7:21 left to play.
Allen called a timeout at that point, and his team came out of the huddle with renewed energy and defensive effort. But the Big Green tied the score again, this time at 55-all, with 22.8 seconds on the clock.
Penn put the ball in Rosen's hands, and the senior hit the winning basket after creating just enough space for himself on the right side of the arc.
Technically, Penn has regained control of its own destiny in the Ivy League title race. Harvard still has the upper hand in one significant respect, though, as the Crimson will host the Quakers at Lavietes Pavilion on Feb. 25.
Allen has no interest in thinking that far ahead, or in allowing his team to do so.
"Who cares if Princeton beat Harvard?" Allen said when asked for his reaction to the Tigers' victory. "We just sat here for two hours and watched the Penn-Dartmouth game."