BOSTON – With an iconic turnaround Sunday at TD Garden, the St. Mary’s of Lynn girls hockey team is state champion for the first time since 2013.

Top-seeded Notre Dame Academy of Hingham took all the momentum of the Div. 1 state final by tying the score with only 7.3 seconds remaining in regulation, but it was the No. 2 Spartans (23-3-1) that won a well-earned title in triple overtime, 5-4.

Freshman Alyssa Norden scored her second goal with only 2:26 left in the third overtime, finishing off a bid from fellow freshman Bella Freitas (two goals, assist). Senior Gianna Tringale was nails in net to win an impressive goalie battle against Cougars senior Ava Larkin (30 saves), making 14 of her 39 saves in sudden-victory.

The Spartans had to rally twice in regulation prior, avenging last year’s loss in the title game with a nearly entirely new team.

“I’m so proud of the kids, obviously, the game could’ve went either way,” said St. Mary’s head coach Frank Pagliuca. “The goal at the end of the game that we gave up was tough, but the kids just kept playing and stayed focused. They battled and competed their hearts out today, I couldn’t be more proud of them.”

“It’s just amazing,” added Tringale. “Last high school career game at the TD Garden, even if we lost it would be (such) a great experience. But, hey, we won.”

Cougars eighth-grader Emma Burke seemed to take the breath out of the building for the Spartans in regulation’s closing seconds, finishing off the 4-4 game-tying goal on a rebound. What both teams followed with was pure guts.

Teams traded Grade-A opportunities throughout all three overtimes, though Tringale saved the season a few times with her glove and Larkin fended off a chance in front from Freitas at the end of double overtime. The Spartans, with a shorter bench, featured inspiring defensive play from eighth-grader Vanessa Hall and Abby Malcuit, drew four NDA penalties – all committed on Freitas.

The last of the penalties set up the game-winner. Keira Twomey got the puck low to Freitas in the right circle, and she sent the puck toward the far post after deking out Larkin at the doorstep. Norden was there to bury it.

Both of Norden’s goals came after leaving with a notable injury early in the second period. St. Mary’s outscored NDA 4-1 once she was cleared.

“We always worked together, I love being on line with (Freitas),” Norden said of the game-winner. “When I got off (in the second), I was like, ‘I need to play.’ … It kind of changed my game up because right after it happened I scored.”

Perhaps nobody looked as defeated in the moments after the game-tying goal to close regulation than Tringale. She responded as well as one could, especially after NDA got the first five shots of overtime and out-shot the Spartans 7-4 in double overtime.

“(Teammates) are looking at me,” Tringale said. “You got to turn around and just focus for the next shot. … They put their trust on me so I’ve got to put that trust back on them and not dwell on the shot or goal.”

“She was nails, I really believe that she won us that game,” Pagliuca added. “I’m so proud of her, the kid hadn’t started a varsity game until her senior year. So think about how far she’s come.”

The Cougars twice built leads earlier, with Devon Moore scoring in the game’s opening three minutes. After Audrey Zinck tied the score for St. Mary’s three minutes later, Sarah White potted a pair of unassisted goals five minutes apart in the second period for a 3-1 NDA lead.

Norden and Freitas scored less than a minute apart late in the frame to tie things up, and Freitas scored midway through the third for a 4-3 lead.