MONTREAL — The most representative moment of this 4-2 loss for the Montreal Canadiens was Lane Hutson whipping the puck away in frustration after former Boston University teammate Macklin Celebrini dumped it into empty net with 2:03 to go in regulation.

He and his teammates didn’t value it nearly as much as they should’ve in this game against Celebrini’s San Jose Sharks.

Hutson made something good happen with it to open the scoring, but had his goal stolen away by a premature whistle.

Then he found himself on the ice for three Sharks goals.

Hutson also had two of his team’s 20 giveaways, struggled as much as any of his teammates to defend the rush, and was left as flustered by the process as the outcome — neither of which were becoming of a team that’s trying to prepare itself for playoff hockey.

“I feel like we just kind of made it a little easy on them,” Hutson said.

Not what you want to hear after Game 65.

At this stage of the season, the details should be entrenched. And in this game, they should’ve been there, especially against a team the Canadiens got well acquainted with just 12 days ago — in a game of shinny that ended 7-5 Sharks at SAP Center.

They learned that night that if you trade chances with Celebrini, Will Smith and the zone-flying Sharks, you will pay dearly.

Or so we thought they did.

“We had flashes of some really good things, defended hard at times, but I feel like just a little bit of looseness in our game,” said Hutson.

Then he delivered this hard-hitting truth bomb: “It’s so hard because early in the year it’s fine because you think about how many games you have left, but now we’re getting down to every little thing within these games matters a lot.”

Brendan Gallagher wasn’t the only thing missing from this one.

Of course, his absence would’ve been a bit less noticeable had replacement Alex Texier’s net-driving assist not been nullified by that early whistle that cancelled out Hutson’s goal.

Then again, seeing Texier and linemate Phillip Danault err on goals that turned a 1-1 tie to a 3-1 Sharks lead made you wonder what No. 11 was thinking from wherever he was watching from.

“Whether you play zone or man on man, you have to block wrist shots,” said Canadiens coach Martin St. Louis. They’re not one-timers, get in the lane.”

Takes courage. The kind Gallagher always brings.

“That guy bleeds the logo,” said Josh Anderson. “What he means to our group on and off the ice, it’s really hard. I don’t know what else to say. We all love the guy. We know what he brings to the team…”

Again, so was the attention to detail, which was lacking at both ends of the ice.

“Offensively, we died with the puck in the corners instead of getting it out of there,” said St. Louis. “They attack a lot below the goal line and bring numbers below the goal line and we talked about not getting stuck with the puck there. If you’re not able to push the puck up, you have to get rid of it. And if you don’t do that, you don’t spend enough time in the offensive zone.”

And defensively, against Celebrini, who now has 94 points (49 more points than Smith, who ranks second on the Sharks with 45)?

“Similar to McDavid, it’s pace (that makes him so dangerous),” said St. Louis. “Any 50-50 (puck) he’s gone. To me, it’s just being aware of that and erring on the cautious side. You can’t turn pucks over when he’s on the ice. Especially against San Jose. They transition very, very quick, they send it, and there’s no structure that can predict that and take care of that. You’ve just got to be very calculated when he’s on the ice, even in the offensive zone. And you can see when he gets away, he’s dangerous.”

The 19-year-old has killed the Canadiens, piling up seven points in San Jose’s two wins over them.

Surprisingly, the young, run-and-gun Sharks clamped down in the third period Saturday and exacerbated Montreal’s faulty execution.

That’s why Hutson was so frustrated.

That and the reality sinking in that 17 games remain for the Canadiens to solve the same problems that have dogged them all season.

Loose play, faulty coverage, and puck mismanagement coming up the ice have played huge parts in the Canadiens allowing the ninth-most goals per game in the league. They’re all things they didn’t struggle as much with in wins over the Toronto Maple Leafs and Ottawa Senators earlier this week, but after these issues reappeared against San Jose, St. Louis said, “I’m happy we’re playing tomorrow.”

“Fix it now,” he added.

Good idea. Especially against an Anaheim Ducks team that beat the loose and free Canadiens 6-5 last Friday.

Gallagher will be back in the lineup Sunday, but the Canadiens will need much more than his best to avoid the same frustration.