Buffalo, N.Y. -- Marc Del Gaizo thought maybe he was dreaming. There was no other way the freshman defenseman could put into perspective the role he played in helping Massachusetts advance to college hockey's Frozen Four championship game for the first time in school history.

Massachusetts players celebrate a 4-3 overtime victory over Denver in the semifinals of the Frozen Four NCAA men's college hockey tournament Thursday, April 11, 2019, in Buffalo, N.Y. Jeffrey T. Barnes / AP

"It's probably the coolest moment of my life," Del Gaizo said. "Right now it seems like I'm dreaming, but we're off to the national championship and that's all that matters."

Del Gaizo scored 15:18 into overtime to seal a 4-3 victory over Denver in a semifinal game that ended just after midnight Friday.

The Minutemen (31-9), making just their second NCAA Tournament appearance, rebounded after squandering a 3-1, third-period lead and overcame having two forwards - including captain Niko Hildenbrand - ejected for illegal hits to the head.

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The victory continued turning around a Hockey East program that hadn't previously won more than 21 games and was two years removed from a 5-29-2 finish in its first year under coach Greg Carvel.

"That five-win season is still pretty fresh," Carvel said. "The pain from that season has sunk in. The glory of this season hasn't sunk in yet."

That's, in part, because the Minutemen's ride from obscurity to the national spotlight isn't over.

UMass now prepares for its most daunting test in facing defending champion Minnesota Duluth on Saturday. The Bulldogs (28-11-2) advanced to their third consecutive championship game by beating Providence.

Minnesota Duluth beats Providence 4-1 in NCAA semifinals

Coach Scott Sandelin isn't taking Minnesota Duluth's third consecutive trip to the Frozen Four championship game for granted because of how difficult it is to get there.

It wasn't easy for the Bulldogs once again in pulling out a 4-1 victory over Providence in a tightly contested game they sealed by scoring two empty-net goals in the final 33 seconds Thursday night.

Minnesota-Duluth defenseman Dylan Samberg, right front, center celebrates his goal with teammates during the third period against Providence in a semifinal of the Frozen Four NCAA men's college hockey tournament Thursday, April 11, 2019, in Buffalo, N.Y. Jeffrey T. Barnes / AP

Minnesota Duluth (28-11-2) overcame having two goals disallowed in the first period and then killed off the Friars' two-man-advantage in the third period, some three minutes before Billy Exell scored the go-ahead goal with 9:53 left.

"I was nervous as hell when they got the 5-on-3, the way their power play was," Sandelin said. "To be able to do that at that time of the game was a big-time moment. Those are changing, turning points in games. Whether we went on to win that, I was just thrilled to get out of their still tied."

Justin Richards scored twice, including an empty-netter, and Dylan Samberg also scored for Minnesota Duluth. The Bulldogs are attempting to become the first team to win consecutive titles since Denver in 2004-05.

Hunter Shepard stopped 28 shots and improved his NCAA Tournament career record to 7-0.