In front of a raucous crowd of nearly 3,900 at Thompson Arena, Beamish's fifth goal of the season was the culmination of a fevered comeback bid by the Big Green (13-10-5, 9-8-4 ECAC) in the final frame.
With a win against No. 1 Quinnipiac Saturday night, the Green could lock up a first-round bye in the tournament as either the No. 3 or No. 4 seed. As it stands now, Dartmouth is in a three-way tie for fourth place with St. Lawrence and Union as all three have 22 points, trailing Yale (23 points) for third.
At the other end of the ice from where Beamish's goal sent waves through the crowd, freshman goaltender Charles Grant quietly went about stopping 40 Princeton (9-14-4, 7-10-5 ECAC) shots in the draw. It was the most saves by a Dartmouth goalie since Jody O'Neill turned aside 45 in a double-overtime game against Cornell in last year's quarterfinal opener.
Senior captain Mike Keenan gave his team a 1-0 lead 15:08 into the game with a blast from the point that beat Princeton goaltender Mike Condon under his glove and just inside the post to cause Thompson to erupt.
Brett Patterson and Charlie Mosey set up the play with two quick passes deep in the offensive end before the puck landed on Keenan's tape.
Tiger's forward Will McDonald answered back less than two minutes later off a faceoff. Andrew Ammon scored midway through the second and the home team fell behind 2-1 through 40 minutes.
Pushing to try and even the game in the final frame, Dartmouth seemed to have no answers for Condon until the final minutes when Beamish delivered yet another timely late goal for the Big Green.
After Eric Neiley and Mosey worked the play down low and behind the net, Beamish corralled the puck and stuffed it in on the wrap-around on his forehand, benefitting from Condon's confusion with a sea of bodies littering the area around the Princeton net.
For the sophomore from Mississauga, Ontario, late goals are nothing new as Beamish scored a late-game winner against Harvard at home in mid-January.
Two late penalties on both teams in the final minutes set up for a dramatic finish through the extra frame, but Grant was up to the task, making several key saves on the doorstep to keep this one deadlocked at 2-2 through 65 minutes.
The tie was the first at home this season for Dartmouth, who is now 10-3-1 in Hanover as Quinnipiac makes its way up I-89 having lost in overtime to Harvard Friday night for its first road defeat of the year
Once again, the Big Green penalty kill was clutch, shutting down Princeton all four times the Tigers played with the man-advantage. Saturday marks the match-up of the nation's top two penalty-killing squads as Quinnipiac (91.4%) is the only team better than Dartmouth (90.2%) playing down a man in 2012-13.
Faceoff with the top-ranked Bobcats is set for 7 p.m.