Islanders' last game at Coliseum? If it was, they sent it out with a bang.

The Islanders may very well have played their last playoff game at Nassau Coliseum. That won’t be known for another couple of days. If it turns out they have, at least they will know they sent the old building out with a bang, beating the Tampa Bay Lightning, 3-2, in overtime Wednesday night.

Anthony Beauvillier scored the goal that tied the NHL semifinal series at three games apiece and forced Game 7 Friday night.

That game will be in Tampa, and the Islanders will need to beat the defending Stanley Cup champions on their home ice to win the series and advance to the Stanley Cup final, in order for there to be more games at their beloved Old Barn.

If they don’t, then the 2021 playoff run will be done. But at least the Coliseum would have been given a proper sendoff.

The building rocked on Wednesday. The fans were into it from the first notes of the National Anthem, when they sang along with singer Nicole Raviv. They positively exploded with noise when Matt Martin threw his first heavy bodycheck of the game, then they got quiet when Brayden Point scored the game’s first goal for the Lightning at 16:02 of the first period. They got quiet again when Anthony Cirelli made it 2-0 at 12:36 of the second period.

But they got loud when Jordan Eberle scored the first Islanders goal less than two minutes later, at 14:22 of the second. They got louder when Scott Mayfield tied it, 2-2, at 11:16 in the third period, and they roared as the Islanders killed a late Lightning power play in the third period. Ultimately, the building got what it deserved in its potential swan song: Overtime.

It was one more night to remember from a building that has had many great nights since the building opened in 1972. Julius Erving and the New York Nets won two ABA championships there, including the final one in 1976, before the league merged with the NBA. The New York Arrows, with Steve Zungul and goalkeeper Shep Messing, won the first four Major Indoor Soccer League championships in the Coliseum.

There was professional wrestling and World Team Tennis, and of course, the New York Saints of NLL, not to be confused with Boston Bruins coach Bruce Cassidy referring to the Islanders as "The New York Saints’’ during the Isles’ six-game victory over the Bruins in the last playoff round.

Whatever happens on Friday, there will be games at the Coliseum in the fall. The Long Island Nets, of the NBA’s G League, play there, as do the New York Riptide, the box lacrosse team that plays in the National Lacrosse League. And there’s also the very real possibility that the Islanders themselves may play some more games in the Barn at the start of next season, as their new home, the UBS Arena, in Elmont, likely won’t be ready in time for the start of the 2021-22 season.

"The Coliseum is historic and loved,’’ said Nick Mastroianni II, Chairman & CEO of Nassau Live Center, LLC, which operates the Coliseum. "We suspect the cheers of Islanders fans will echo inside for many years to come with the championship banners hanging. But it is also a space that is going to be reinvented as a 21st Century venue that attracts a new generation of Long Islanders with programming that is exciting, compelling, and successful.’’

By Colin Stephenson

colin.stephenson@newsday.comColinSNewsday

Colin Stephenson covers the Rangers for Newsday. He has spent more than two decades covering the NHL and just about every sports team in the New York metropolitan area.