MANCHESTER, N.H. – The trend wasn't lost on Cal Petersen. The Notre Dame goalie knew that on the first day of the NCAA men's hockey tournament, teams had rallied from two-goal deficits, so he didn't worry that the Fighting Irish were sunk when the Gophers seized a 2-0 lead Saturday in their Northeast Regional semifinal.

"We talked before the game about how it's not over until the full 60 [minutes],'' he said, noting how calm his team was as it regrouped during a second-period timeout. "We knew the game was on the line, and the next goal was huge.''

It turned out to be transformative. The 12th-ranked Irish scored twice in the span of 54 seconds, then netted the only goal of the third period to upset the top-seeded Gophers 3-2. Though the Gophers got the start that coach Don Lucia wanted, they could not finish, losing in the first round at SNHU Arena just as they did in 2015.

Connor Reilly got his first goal of the season at 2 minutes, 7 seconds of the first period, and Vinni Lettieri made it 2-0 with a power-play goal 30 seconds into the second. The highlights for the Gophers (23-12-3) ended there. After controlling much of the first 30 minutes with smart, disciplined hockey, they withered as Notre Dame (22-11-5) gained energy and rode Petersen's strong goaltending.

A bad line change by the Gophers led to Notre Dame's first goal, scored by Andrew Oglevie at 14:39.

Anders Bjork tied it less than a minute later, then added the winner on a power play at 8:42 of the third.

The Irish will play UMass-Lowell, a 5-0 winner over Cornell in Saturday's first game, in the regional final Sunday.

The Gophers will lament the missed chances and mistakes that created a rueful ending to a game that had begun so well.

"I thought we had the start we wanted,'' Lucia said. "Even through the second period, the one concern I had when we were up 2-0 was I thought we left some opportunities on the ice, where maybe we could have extended that lead.

"[The two Notre Dame goals] really changed the momentum of the game," Lucia said.

"I'm proud of our guys. Notre Dame played a good game like we knew they would and, unfortunately for us, we didn't make that one more play to extend the game into overtime.''

The fourth No. 1 seed in the tournament, the Gophers were the only top seed to lose their opening game.

Notre Dame won an NCAA tournament game for the first time since 2011, when the Irish went to the Frozen Four.

Lucia's heart ached for the Gophers' six seniors, including five who were part of the team that lost in the NCAA championship game in 2014. They made it back to the tournament twice but never got past the first round. Saturday, two of them — Reilly and Lettieri — provided the goals, and a third, Taylor Cammarata, had an assist.

Most everything went right for the Gophers in the first 30 minutes. They played with strength and confidence, outshooting the Irish and putting some heat on Petersen.

At 10:28 of the second period, Notre Dame coach Jeff Jackson used his timeout to give his team a breather and talk things over.

The Irish came back revitalized. The poor line change by the Gophers opened a path for Petersen's long outlet pass to Oglevie, who finished off a two-on-one. A strong Notre Dame forecheck led to Bjork's tying goal.

Gophers winger Tyler Sheehy said his team remained positive. "They scored two quick goals, and the momentum shifted a little to their favor,'' he said.

"Ultimately, you have to win a period to win a game. They got one in the back of the net, and we had a few chances we couldn't capitalize on.''

The Gophers got three power-play opportunities in the final 21 minutes, but they failed to score.

Near the end of the game, senior captain Justin Kloos banged a shot off the goalpost, ending his Gophers career in frustrating fashion.

"I feel bad, especially for our seniors,'' Lucia said. "I'm deeply disappointed we weren't able to extend our season.''