DETROIT — Maybe it was the third or fourth goal of the final period that did it.

The players insisted the turning point in Saturday’s game came earlier, that it was the shot that put Notre Dame on the board in the middle of the second.

But it was hard to count Michigan out with so much time left and in such an important game.

For the Wolverines, who absolutely rocketed through the past few months and built their reputation as a second-half team, it was the entire second half of the CCHA Championship game that failed them.

Something snapped. Whatever it was — be it goaltending or turnovers or determination — completely shrunk Michigan’s confidence level and momentum heading into the NCAA Tournament.

And no matter what caused the third-period meltdown, the fact that it happened must be addressed if the Wolverines want to be a legitimate national championship contender.

“If we play like (Saturday), then our next game will be our last game,” Michigan coach Red Berenson said after the 5-2 loss.

After all, nobody expected a third-period collapse — the Irish’s four-goal frame coupled with Michigan’s measly eight shots on goal. Prior to Saturday’s game, the Wolverines had outscored opponents 51-30 in the third this season.

Maybe the pressure got to sophomore goalie Bryan Hogan. It was just the fourth postseason start of his career, and the matchup had been intimidating with Hogan stacked against vaunted Notre Dame senior Jordan Pearce, one of the best netminders in the nation.

The Wolverines argued it wasn’t just one player that cost them the game, and they're right. It wasn’t just Hogan giving up those goals. The Michigan defense, an overlooked and underrated strength of this team during its hot second half, fell apart. Irish forwards had no trouble intercepting passes or navigating the Wolverine zone, and Michigan, a team that prides itself on blocking shots, tallied just one block in the final period.

“Goals against are precious this time of the year,” senior defenseman Mark Mitera said. “Defense is what’s going to win us games this (coming) weekend. Two goals for, five against — you’re not going to go anywhere.”

It’s hard to call Saturday’s loss a wake-up call for the Wolverines. With just a handful of games left in the season at best, Michigan knew it couldn’t play a sloppy period like that.

But now, the Wolverines have no choice but to learn from the loss and move on.

They’ve learned they can’t just hope a one- or two-goal lead will stand up against the nation’s best competition. They have to maintain it with smothering defense, consistent goaltending and solid backchecking.

They’ve also learned they have to play desperately, like the Irish did, with the season on the line — which, from now on, is every time they step on the ice.

“Where we’re at in the season, no loss is a good loss,” junior defenseman Chris Summers said. “We have a week to prepare for next weekend, and it’s do-or-die from there.”

— Auerbach can be reached at naauer@umich.edu.