The game, held at Bedford Field, was the Ivy League opener for both teams.
The Big Green (1-4), looking to upset the highly-ranked Tigers (5-0) for the second year in a row, fell behind early as the home team and defending League champions took a 1-0 lead just 5:08 into the game.
Keeping Princeton off the scoreboard for the rest of the half, Dartmouth trailed by just the one at intermission. However, two goals just over a minute apart early in the second half pushed the deficit to three. One more tally from the Tigers in the second made it a four-goal game.
But with just over 12 minutes remaining in the contest, Masini stepped up and delivered her team-leading third goal of 2012 on a penalty corner. The Second Team All-Ivy player from a year ago, who excels at the pushout to start the set play, once again was able to get a stick on the ball and redirect the pass into the back of the goal.
The Dartmouth marker snapped a stretch of 215:35 without a goal for the Green and White, dating back to a Sept. 2 home game with Northeastern. Masini remains the only player on the team with more than one goal this fall as she scored twice in the season-opening win over UMass on Aug. 31. She had four goals in all of 2011.
Assisting on the goal was sophomore Janine Leger (Johannesburg, South Africa) for her first point of the 2012 campaign.
For the first time all season, head coach Amy Fowler went with one keeper for the entire 70 minutes of action. Senior Jenna Stearns (Thornton, N.H.) was up to the task as she faced off with one of the top offensive teams in the nation and turned aside seven shots on the day.
Princeton held advantages in shots (27-5) and penalty corners (13-4), while Stearns' seven saves were six more than Tigers' goalkeeper Christina Maida posted at the other end of the field.
The Big Green will return home for two games at Chase Field next week after playing the last three on the road. A non-conference, mid-week tilt with Bryant on Wednesday (3 p.m.) is followed by it's first home Ivy game on Saturday afternoon (12 p.m.) when Brown makes the trip to Hanover.