How High The Moon — An all-time hit song.

How high the Islanders?

That’s the talk around the National Hockey League now that coach Barry Trotz‘s astonishing outfit did what — last Fall — nobody in the ice world thought they could accomplish.

They have done what the Las Vegas Golden Knights did in the regular season last year; fool the experts.

Yes, they are in the playoffs! (I repeat if you still don’t believe it: THE ISLANDERS ARE IN THE PLAYOFFS!)

Convincingly, they kept the pedal to the metal in routing the Buffalo Sabres, 5-1, on Saturday night at the Coliseum, as the enthusiastic crowd roared their approval.

Brendan Burke and Butch Goring look at how the Isles sealed a playoff berth with a 5-1 thrashing of the Sabres at the Coliseum.

No, they didn’t back into the post-season. During the most pressure-packed homestretch, the Isles (46-26-7) won four of their last five games. Incredibly, they clinched ahead of the Toronto Maple Leafs who visit Uniondale on Monday night.

In the Islanders’ 46-year history, the Nassaumen have produced a number of startling surprises, but this latest shocker ranks very high among the all-timers. It marks their first playoff appearance since 2016.

Heroes were in abundance, but Anthony Beauvillier scored the playoff-entrance game-winner and had two red lights for the night.

Once again, Robin Lehner showed why he’s a top Masterton Trophy candidate with a 31-save effort.

To put this miracle on ice in perspective, remember it was the sage editors at the sport’s “bible,” The Hockey News, who picked the Isles to finish eighth in the Metro Division. “They are trending downward,” THN had mistakenly asserted.

Call the Isles’ accomplishment another hockey miracle or call it what you will; either way, it suggests a lot of things. But it begs the question: against all odds how did Trotz’s warriors pull it off? Okay, everybody here’s how:

1. Ownership was wise in hiring Lou Lamoriello as general manager and Lou was sage in bringing Cup champ Trotz in as head coach.

2. Trotz instituted a firm defensive system that allowed the club to drastically trim goals against — a ghastly NHL worst 293 last year — while still producing enough red lights to win the almost-always close games. Mocked last season, the Isles’ blue line corps metamorphosed into one of the league’s best units.

3. Meanwhile, the coaching staff integrated newly acquired forwards Valtteri Filppula, Leo Komarov, Tom Kuhnhackl and Matt Martin into the lineup. They fit like perfectly meshed gears.

4. Lou took a gamble on goalie Lehner who went on to prove that he’s capable of being a No. 1 netminder. The Sweet Swede responded with a career year. Meanwhile, his able sidekick, Thomas Greiss lifted his performances to a career-high level.

5. The choice of Anders Lee as captain — replacing John Tavares — turned out to be as excellent as any decision made by the high command.

Anders Lee talks how his team used the momentum from the last win into this game and what they need to focus on moving forward.

6. Each time the team slumped throughout the marathon campaign, skeptics anticipated a tailspin right out of playoff contention. As it happened, such a fatal plunge never took place.

“We bent,” concluded Trotz, “but we never broke.”

That was possible thanks to Trotz’s precise game plans. One of them meant that dipsy-doodle dandies such as 2018 rookie-of-the-year Mathew Barzal had to refine his game with an accent on backchecking as well as free-wheeling in the other direction.

Barzal accepted his new role and gradually — not instantly, mind you — adjusted to the improved system.”I like the big games, the pressure,” said the sophomore who proved it as he starred in the critical, turning-point win in Winnipeg on Thursday night.

Lehner delivered in that unreal, come-from-behind thriller as he has done throughout the season. If nothing else, his acquisition proved to be another Lamoriello genius move. “I’m having fun here,” said the big goalie. “It’s a positive atmosphere.”

After Saturday night’s triumph, that last observation may be the understatement of the half-century.

Adding to the positivity was the manner in which Lamoriello’s once-derided acquisitions proved their worth; Exhibit A being the marvelous two-way play of Filppula. Before his recent injury, the Flying Finn had totaled 15 goals and 29 points.

By importing Martin back to the Island-Brooklyn, Lamoriello re-created “The Best Fourth Line In The League” with Cal Clutterbuck and Casey Cizikas making beautiful music together.

“For us to succeed,” said Trotz, “we needed all four lines going. It had to be a team effort.”

After clinching a playoff birth for the first time in two years, Barry Trotz talks about the Isles work ethic and how it feels to make it further than anyone expected.

That it was in Winnipeg where the Isles’ late third-period explosion startled everyone from Manitoba to Manhasset.

“It was our biggest win over the season,” said defenseman Ryan Pulock, the budding star with the blazing shot.

Brendan Burke and Butch Goring go over the action from the Isles' 5-4 win over the Jets in Winnipeg.

As for captain Lee, he remembers the naysayers of October. To them, he had this perfect squelch: “A lot of people didn’t think it would happen.”

Then, a pause: “Except the guys in this room!”

P.S. Where the Islanders go from here will depend in large part on where they finish the regular season campaign and which foe they will meet in the post-season. Time will tell.

But that’s for later. For now, jubilation reigns sky-high in Uniondale and wherever Islanders fans choose to toast their favorites.

How high the Islanders?

As Trotz’s troops have demonstrated, you never can tell.

Who knows? This miracle could be followed by another!

[Watch the Isles Host the Maple Leafs Monday on MSG+2 & MSG GO. Get the App Now.]