PHILADELPHIA -- Sometimes what ends up being more important is what you don't do.
Boston College coach Jerry York thought a key in Thursday's national semifinal loss to Union College was when right wing Daniel Ciampini scored a power-play goal at 6:31 of the third period to give the Dutchmen a 3-2 lead.
But the real key started 18 seconds later, when Ciampini's teammate Matt Hatch was whistled for checking from behind against BC center Michael Sit.
The major penalty and corresponding game misconduct meant that the high-powered Eagles' attack would have a five-minute man-advantage to even up the game and possibly take a lead.
Union didn't panic. And Boston College didn't capitalize.
The Dutchmen allowed only three shots on goal on the penalty kill without giving up a score, and never surrendered the lead en route to a wild 5-4 win at the Wells Fargo Center in the first Frozen Four semifinal.
The victory extended Union's unbeaten streak to 16 games (15-0-1) and advanced the Dutchmen (31-6-4) into Saturday's national championship game versus second semifinal winner Minnesota (7:30 p.m. ET, ESPN/WatchESPN). The Gophers move on thanks to Justin Holl's goal with 0.6 seconds remaining that gave Minnesota the win over North Dakota in Thursday's nightcap.
Boston College suffered its first loss in the national semifinals since Maine beat the Eagles 2-1 back in 2004. Since that defeat, the Eagles have appeared in five finals, winning three titles (2008, 2010, 2012).
The Eagles jumped out to a 1-0 lead against Union just 2:08 into the game when left wing Johnny Gaudreau scored his 36th goal of the season. Prior to Thursday's game, BC was 18-0-2 when leading after one period and 17-0-1 when the presumptive Hobey Baker Memorial Award winner played a role in the game's opening goal.
"I thought the power-play goal in the third period, the shot from the point, was a turning point in the game," York said. "We had to answer it with our five-minute power play but we just never quite got in sync with that major penalty."
To make matters worse, BC defenseman Steve Santini got stripped of the puck by Union right wing Kevin Sullivan just after the power play expired. Eagles goalie Thatcher Demko made an impressive save on the initial breakaway shot by Sullivan, but the freshman netminder had no chance when Sullivan fed the rebound from behind the net to a streaking Mike Vecchione, who easily buried the puck past Demko for a 4-2 Union lead with 8:07 remaining.
"I think we gained confidence once that kill was over," Union captain Mat Bodie said. "To score that goal was huge. They're a dangerous team and I've never seen a team battle to the end like they [did]."
Not only did BC, which finished the season at 28-8-4, fail to score with the man-advantage, but the Eagles trailed by two goals and were forced take chances to get back in the game. York's club made it closer than it should have been but the long offseason will be spent reviewing what didn't happen during that lengthy man-advantage opportunity.
"I thought we were a little bit out of sync with passing the pucks a little too slowly, not quick enough, and then it's easier for the [shooting] lanes to be blocked," York said. "But I think during the course of the night we played pretty good hockey here. And I don't want to take anything away from the other club."
Indeed. Full marks go to Union and its complete play in all three zones. But particular praise goes to the PK units and goaltender Colin Stevens for staying in unison while the Eagles scrambled to do something, anything with its good fortune.
"When [the penalty] happened, the team talked on the bench and just said it's time to bear down," Bodie said. "It was an unfortunate play for Matt Hatch. We're a family in here and he's one of our brothers and we didn't want him to go out that way."
Union improved to 16-1-2 against nationally ranked teams this season, with the only loss coming at Quinnipiac back on Jan. 10.
"They're a great shot-blocking team," BC captain Patrick Brown said of Union. "I was net front and I couldn't even see the puck because they had two or three guys in the lane every time. But we didn't create enough movement, get pucks to the net around them.
"And credit to them. They played unbelievable."
Because Union didn't give up a goal during the five-minute penalty kill, it was rewarded and gets to play one final game.
And because BC didn't find a way to take advantage of its best chance to extend its season, the Eagles have been reduced to spectators on the final night of the college hockey season.