ORONO — As good as the defensive statistics have been throughout the season, the University of Maine men’s hockey team knows its defense has been a season-long work in progress.

“Obviously, there’s going to be ups and downs for any D corps throughout the season. I think it’s just learning from mistakes from previous games and being able to build on those,” said senior defenseman David Breazeale, one of Maine’s captains.

The defensemen have worked closely with assistant coach Jason Fortier on cleaning up the little mistakes that can prove costly. From clearing the puck out of the defensive zone to making sure goalie Albin Boija gets a clear look at the puck, the Black Bears are doing everything better of late.

“I think we just take a lot of pride in keeping the puck out of our net. We’ve worked so much on so many little things,” said Brandon Holt, who last week was named an all-Hockey East third-team selection. “If we have a chance to get it up and make a good play, it makes it so much easier on the forwards.”

Maine ranks third in the nation in scoring defense, allowing 1.86 goals per game, and ranks seventh in scoring margin (1.40).

“When we’re using our feet, we’re confident with the puck. We’re looking to advance plays cleanly,” Breazeale said. “That’s when we’re playing our best hockey, because we allow our forwards momentum to carry pucks through the neutral zone and into the offensive zone. I think that’s something we’ve really built on.”

The Black Bears take on Northeastern Thursday night at Boston’s TD Garden in the Hockey East semifinals. A win sends Maine to the conference final for the first time since 2012. Maine hasn’t won the Hockey East championship since 2004. No matter how the Hockey East tournament plays out, the Black Bears know they’ll be in the NCAA tournament field for the second consecutive season when it’s announced Sunday.

Coach Ben Barr said he’s seen improvement across the board since midseason when he admitted there were games in which he wasn’t sure each of his defensemen was able to play mistake-free hockey from shift to shift.

“Having Luke Antonacci and Bodie Nobes playing well is really, really important. Those guys have given us great minutes, which allows Jason to roll six or seven D. That makes everyone else better,” Barr said.

There were times during the middle of the season, it seemed as if Maine’s defenders were timid with the puck, and that led to mistakes that turned into scoring chances. Often, those mistakes were covered by the stellar play of Boija, who is among the best in the nation in both goals against (1.75) and save percentage (.930). On Wednesday, Boija was named a finalist for the Mike Richter Award, given annually to the top goalie in the nation.

“When mistakes are made, those are big mistakes. A forward, you can make a mistake in your offensive zone and maybe it doesn’t end up in the back of your net every time,” Barr said. “With a defenseman, you make a bad turnover, a bad decision or whatever, it’s a scoring chance a lot of the time. That’s the nature of the position.”

Sophomore Frank Djurasevic, who transferred to Maine this season after spending his freshman season at Merrimack, said the Black Bears’ defensive unit relies heavily on chemistry. Earlier in the season, Barr mixed and matched defensive pairings, trying to find the right combinations. Over the last few games, the three defensive pairings have been more stable with Breazeale and Brandon Chabrier the top pair, followed by Holt and Djurasevic, with Antonacci and Nobes the third pairing. Lately, Grayson Arnott has been used as a seventh defenseman.

“Right now, at this point in the season, it’s just doing our job. We’ve got to tighten up, especially defensively. We’re playing some good teams with really good skill,” Djurasevic said. “We’ve got some bigger guys, some guys who can skate, a little bit of everything. We’re trying to use that depth.”

Nobes, a sophomore who played 19 games as a freshman last season, has been a source of consistency since the start of January, Barr said. Inserted into the lineup for the first time when Maine hosted defending national champion Denver on Jan. 3, Nobes has been in the lineup for every game, going plus-7 with four assists, including two in Saturday’s 7-1 Hockey East quarterfinal win over UMass Lowell.

Antonacci’s play has improved in recent games, Barr said, because he’s found his confidence again.

“When he’s a confident kid, he’s super effective. When he’s not, it’s turnover, turnover, turnover, turnover. That’s not just him, that’s anybody. He’s put the work in and he’s found his game,” Barr said. “It’s really just a composure and poise thing. You can tell when a guy wants the puck on his stick when the puck comes to him, and what happens with it after. You can’t really coach that stuff. You can show it, but confidence is one of those things where you have it, and if you don’t have it you have to find it.”

That mental acumen was tested Saturday when Chabrier was ejected from the game in the final minute of the first period for butt-ending a Lowell player. That left the Black Bears with five defensemen for two periods. It meant shorter shifts and a keen attention to detail were essential. It was also a throwback to those games earlier this season when defensive pairings were likely to change game to game.

“We all have the same mindset when we go out there, so that makes it pretty easy to play with each other. I enjoy mixing it up. It’s something new once in a while. I’ve been playing with Chabrier a long time now and that’s been fantastic,” Breazeale said.