Islanders’ top line give exciting glimpse of what it’s capable of

The Islanders have wanted a top line like this one for years, and they didn’t have to wait long to see what it could do.

It was the preseason — in fact, it was a loss in the preseason in which the Islanders blew a three-goal lead by melting down and giving up six goals in the third period — so take it with whatever size grain of salt you like.

But any night where the line of Anthony Duclair, Bo Horvat and Mathew Barzal scores three times on its debut — even in a 6-4 loss to the Rangers at the Garden — counts as one the Islanders can feel good about.

“Played alright,” Barzal said, in understated fashion. “Had some good looks. Fortunate enough to bury a few. Would’ve liked to get that six-on-five [goal against] back. It was an alright start for us.”

Islanders coach Patrick Roy has mixed and matched most of his lines during camp and, as expected, hasn’t committed to anything in terms of what the lineup will look like on Oct. 10 against Utah.

But Duclair, Horvat and Barzal have been together throughout camp so far, and nobody is bothering to keep it a secret that they will be together on opening night.

That is, quite literally, the reason Duclair is here. And it showed quickly as he orchestrated a give-and-go with Barzal on the night’s first goal.

“Seems to always be open,” Barzal said of Duclair. “I thought he was great.

“Just had to watch and can tell he’s easy to play with. He’s a bigger guy than I thought he was. He’s good with winning battles, getting in corners and he’s not afraid to hang onto it down there. Think that’s gonna be the key for our line is turning over pucks in the transition game.”

The Islanders had seven different players with Horvat and Barzal last season. If the number this year even approaches that, it means something has gone quite wrong.

If this was the first look, then it’s tantalizing to think what this could become down the line.

That is something to get excited about indeed.

Roy said he plans to be behind the bench for every preseason game as opposed to watching from higher up, as some coaches opt to do.

Mike Reilly skated on Tuesday after missing Monday’s practice with illness.

Semyon Varlamov stopped all 10 shots he saw before being relieved by Henrik Tikkanen, who allowed five goals on 13 shots.