The morning’s undertones told you that the Islanders lineup could look different awfully soon. The evening’s overtones told you that might be a good and necessary thing.

It looked for much of this game like the Islanders were on a glide path to getting away with two points too, even with nothing like their best performance. Given the not-quite-official fight between Matthew Schaefer and Luke Hughes that saw Schaefer hand a beating to the youngest member of hockey’s first family, it would have been about as happy a win as the Islanders could have asked for before taking off for California on Sunday, had they hung on to a 4-2 lead.

Instead, their performance caught up with them. The Islanders frittered away a two-goal lead in the last 20 minutes to make it a winless three-game homestand, handing the Devils a 5-4 win on Jack Hughes’ overtime goal that ended a night rife with subplots. Mathew Barzal and Co. can’t make it back soon enough.

The good news on that score is that Barzal and Matias Maccelli shed their noncontact jerseys at Saturday’s morning skate, the next step for both to return to play. The lineup badly needs not only those two but also Calum Ritchie and Ryan Pulock.

As for the lineup head coach Pete DeBoer did have at his disposal, well, it’s never a good thing when pregame line changes get abandoned midway through. The decision to take Scott Mayfield out of the lineup and leave the Islanders short on penalty killer was a head-scratcher as well.

This, though, was much more about the Islanders struggling to get to their game than any coaching decision. Even in getting out to a 4-2 lead, the Islanders never had a forecheck and never put extended pressure on the Devils zone.

More than anything, the difference going into the third period was goaltending — one accentuated even more when Ilya Sorokin stretched out his right pad to deny Nico Hischier at the backdoor 1:01 into the final period.

The goaltending from Sorokin, who stuck out the same pad to deny Hischier a second time a little more than five minutes later, was a sign of the chances the Islanders were bleeding. Luke Evangelista cut it to 4-3 on a shift that saw Sorokin make multiple acrobatic saves before the Devils finally stuck one by him at the 6:08 mark.

The decision to go one penalty killer short bit the Islanders late in the third, as did an in-arena replay that seemed to influence the (correct) high-sticking call on Adam Pelech that put the Islanders at 5-on-3 at 12:35 of the third.

After killing off the two-man advantage, the Islanders — who had leaned heavily on Pelech at 4-on-5 all night along with Logan Stanley — let up a power-play goal on a Dougie Hamilton one-timer that tied the game.

The Islanders hung on for a point but couldn’t steal a second.

They had a gripe on a potential trip of Schaefer that led into a 2-on-0 break that Jack Hughes promptly finished.

It’s a little ironic that on what could have been Connor Hellebuyck’s first game for the Devils against the Islanders, New Jersey got the sort of goaltending from Jake Allen that reminded everyone why they needed the Team USA superstar to begin with.

Allen surely should have gloved the Tony DeAngelo shot that instead went off his leather for Victor Eklund to drive to the crease and make it 4-2 at 11:54 of the second, and the goaltending disparity was obvious for long stretches on a night when Sorokin had it going in the opposite net.

Despite the Devils having the better of the run of play, the two teams traded goals back and forth for the early going. Evan Rodrigues scored just 17 seconds after Anthony Duclair’s opener; Simon Holmstrom put the Islanders up 3-2 all of 26 seconds after Declan Chisholm tied it at two for the Devils.

In between, Schaefer stuffed one in at New Jersey’s crease after Bo Horvat and Emil Heineman did yeoman’s work in keeping the chance alive. Holmstrom’s goal was similar, with Horvat and Kyle Palmieri doing the battling.

If the Islanders had reason to feel they should have gotten more out of this one, it’s that their intensity was there throughout. They were outplayed, not outworked.

And they’ll hope the reinforcements are coming soon.