One of the things that makes professional sports so popular is the feeling that a team and its fans are in it together. They travel through a season side by side. That is a nice notion, and in the case of the Islanders, it is actually true. So that was why the players were so grateful Sunday night.

Islanders players know about the sacrifices and inconveniences that their fan base endured this season because, by and large, they endured them, too. The move to Brooklyn was tough on everyone, what with the hassle of commuting and the disorientation caused by new routines. The team took it all in stride, riding the Long Island Rail Road to a good first season at Barclays Center and continuing it with a thriller of an inaugural playoff game Sunday night.

Players were pleased and impressed that their fans did the same. The Islanders know a fan’s challenges and expenses of catching a train, as opposed to loading up a van and paying one parking fee. They know that the nights can grow late when you have a longer ride home. They understand that, unlike the players, most fans do not have the benefit of postgame car services — and that also unlike the team, most spectators did not have the luxury of a day off after an 8 p.m. start.

The players appreciated it, all of it. “They’re amazing. It’s unbelievable how passionate they are. They want to win just as bad as we do,” said Shane Prince, a trade-deadline acquisition who experienced his first home playoff game as an Islander. “We need them behind us every home game.”

First and foremost, that includes Wednesday night, when the Islanders have a chance to achieve a feat they have not accomplished since 2002 by winning a second straight playoff game.

Regardless of the vocal support they had at Nassau Coliseum, the postseason has been a rough road for the Islanders since 1993, when they last won a series. The drought just showers more credit on fans who keep showing up, bringing their hopes and their obviously capable lungs.

Jack Capuano said he grew hoarse trying to shout instructions over the noise Sunday night. Rookie Ryan Pulock, who scored a huge goal, said, “The fans were incredible from start to finish.”

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Thomas Hickey said he felt goose bumps amid the din right after the national anthem. He would have experienced more of those had he heard the loud chanting of his name in the stairwells after he beat the Panthers with an overtime goal, giving his team a 2-1 edge in the series. He said of the atmosphere, “I thought it was incredible.”

On another level, though, it was perfectly normal. Most successful teams have great and loyal fans. The Islanders always have enjoyed an extra layer of closeness that came with being in the suburbs. In the early years, they spent summers playing softball games with local people. Some players liked the homespun feeling so much that they settled on Long Island. Clark Gillies did that. So did Bob Nystrom, Jean Potvin, Pat LaFontaine and Benoit Hogue (following the lead of Buzz Des champs and some of his teammates on the endearing Long Island Ducks).

We will see if there is a future for that kind of symbiosis now that the Islanders play inside the New York City limits. Who knows if the first-night excitement will carry over, or if the Islanders can turn it into victories?

Whatever the case, after one playoff game, the Islanders recognized what went into giving them such a boost. They appreciated every last decibel. They are their fans’ biggest fans.