In the first period of its emotional rematch against Dartmouth, Harvard sprinted out to a 3-0 lead. The Crimson ended up needing every one of those goals as it held on for a 4-3 win at the Bright Hockey Center on Friday night.

With the victory, No. 6 Harvard (19-6-3, 16-1-2 ECAC) clinched a share of the ECAC title and the top seed in the conference tournament. The Crimson toppled the No. 3 Big Green (23-4-0, 16-3-0) for the second time in three weeks, earning a regular-season sweep of its Ancient Eight rival and the Ivy League championship.

After Dartmouth narrowed the deficit to one goal late in the second period and the momentum appeared to be shifting, sophomore defenseman Lindsay Weaver notched the eventual game-winner. With little over a minute remaining in the frame, Weaver gathered the puck along the right boards on the edge of the Big Green zone. She then uncorked a low-flying wrister that skidded along the ice, through the traffic in front of the net, and past Dartmouth goalie Kate Lane, just squeezing inside the post.

“I was just trying to throw it on net for a tip,” Weaver said. “It just went in. It was a surprise and it was good.”

“Being able to score that goal helped reassert the fact that we were in the lead and still in control of the game,” tri-captain Nicole Corriero said.

But the Big Green trimmed the Harvard advantage back to a single score at 4:37 of the final period, when Dartmouth’s Cherie Piper skated through the defense and beat netminder Ali Boe high and tight. The next 15 minutes, as the Crimson fought to maintain the one-goal margin, were filled with an anxiety befitting the rivalry and its history of intense, narrowly decided games.

“I knew it was going to be a close game,” Harvard coach Katey Stone said. “We had no delusions they weren’t going to score goals tonight.”

It was just a matter of getting one more than they did. The most nervous moment of the sequence came with 4:33 left in the contest, when Corriero got tangled up with her defender and went airborne before crashing to ice. For several seconds, the scoreboard showed Corriero being assessed the lone penalty on the play, and the crowd of 1,611 moaned in disapproval. The mess was quickly sorted out, with Corriero getting two minutes for diving, and Dartmouth’s Alana BreMiller taking a foul for holding her.

“We didn’t want to back off at all,” Corriero said. “When you back off and try to hold on, that’s when you get in trouble.

We wanted to play smart. Keep putting on the pressure, keep forechecking, but don’t take any risks.”

The penalties were just two of a total of 22 handed out on the evening, in a physical matchup that yielded 18 power plays and three power-play goals.

“It was a tough game to call,” Stone said. “It was very physical, more than the last one had been. We did a good job overall of shutting them down.”

The first of those power-play goals came on a Harvard 5-on-3 late in the first period and pushed the lead to a healthy 3-0. Senior Ashley Banfield picked out Corriero at the left post for the easy one-timer, her nation-leading 47th goal of the season.

The Big Green got back in the game with two man-advantage tallies of its own in the second period. Meagan Walton brought the score to 3-1 at 11:48, and Dartmouth threatened again with a 5-on-3 of its own soon after. A bunch of dazzling saves from Boe kept the Big Green off the board, but with the first penalty killed off, and seconds winding down on the other, Gillian Apps found Katie Weatherston for a goal.

“They have weapons all over the ice,” Stone said. “If you give them time and space, they’re going to hurt you.”

This flurry came on the heels of a breezy opening period for Boe—who finished with 20 saves—in which Harvard outshot a lethargic Dartmouth squad 20-3 and built a sizable cushion.

Harvard struck for the first time a mere 3:38 into the game, on a well-executed 2-on-1. Tri-captain Kat Sweet carried the puck up the right side and dished it to sophomore Katie Johnston in front who went top shelf on Lane for the goal.

Three minutes later, the lead doubled. Off a face-off in the Dartmouth end, sophomore Jennifer Sifers corralled the puck behind the net and sent a seeing-eye centering pass across the crease.

Carrie Schroyer and Laura Brady, crashing the net, both got their sticks on it, with Brady awarded the goal and Schroyer the first assist.

—Staff writer Jonathan Lehman can be reached at jlehman@fas.harvard.edu.