UNIONDALE, N.Y. — Islanders captain John Tavares was still attempting to gather his bearings after being leveled in the corner, when he heard the familiar – and welcome – roar go up inside the Nassau Veterans Memorial Coliseum for what could be the last time.

“Yes! Yes! Yes!” the orange towel-waving crowd yelled in unison as part of its traditional goal chant.

Sparked by Tavares’ rush, Nikolay Kulemin scored the go-ahead goal with 9:27 left in a 3-1 victory over the Washington Capitals on Saturday that forced a seventh game in the first-round playoff series.

When did Tavares know the Isles had scored?

“Just when I saw everyone going crazy,” Tavares said. “I’m just happy it went in.”

Tavares had a goal and assist, Nick Leddy had two assists, and Cal Clutterbuck scored into an empty net with 53 seconds left.

Now the two Metropolitan Division rivals who finished the season with 101 points each will meet Monday night in Washington to decide who advances to face the Presidents’ Trophy-winning New York Rangers.

Tavares and the Isles were excited to reward their home fans with a win.

“We want to keep this thing going. We want to be able to play in front of them even more,” defenseman Brian Strait said. “To not keep it going, it doesn’t matter. It’s a failure.”

John Carlson scored for the Capitals, who had won the previous two games, including a 5-1 win on Thursday.

RED WINGS 4, LIGHTNING 0: Petr Mrazek stopped 28 shots and Detroit rebounded from a disappointing loss to win at Tampa, Florida, and take a 3-2 lead in their series.

Riley Sheahan, Drew Miller, Pavel Datsyuk and Danny DeKeyser scored for the Red Wings. They can close out the Eastern Conference matchup by winning Game 6 at home Monday night.

The shutout was the second of the series for Mrazek, who had no previous NHL playoff experience before being named Detroit’s starter over veteran Jimmy Howard.

The 23-year-old goalie blanked the Lightning 3-0 in Game 3 at home and also had the only shutout against the league’s highest-scoring team during the regular season.

BLACKHAWKS 4, PREDATORS 3: Duncan Keith scored at 16:12 of the third, and Chicago won at home to take its first-round playoff series 4-2.

Keith beat a screened Pekka Rinne with a shot from the left point. The defenseman, who had the winning goal in a 4-3 double-overtime victory in the series opener, also had two assists in the clinching game.

Jonathan Toews, Patrick Kane and Patrick Sharp also scored for Chicago, and Corey Crawford stopped 13 shots after replacing Scott Darling in the first period after the rookie gave up three goals.

The Blackhawks will face St. Louis or Minnesota in the Western Conference semifinals as they try to finish an up-and-down season with their third Stanley Cup title since 2010.