Washington Capitals defenseman Dmitry Orlov (9) hooks Tampa Bay Lightning defenseman Luke Witkowski (28) during the second period of an NHL hockey game Saturday, March 18, 2017, in Tampa, Fla. (AP Photo/Chris O'Meara) (Chris O'meara/Associated Press)

Before the Washington Capitals faced the Tampa Bay Lightning on Saturday night, Barry Trotz boldly proclaimed it an “absolute must-win game” for Washington. That was a curious statement from the coach of the league’s first-place team, but he was more than ready for the team’s late-season slide to be put to bed.

In a game the Capitals treated like a playoff contest, Washington officially clinched its postseason berth with a 5-3 win over the Lightning. Because the Columbus Blue Jackets beat the New York Islanders earlier in the day, Washington became the first NHL team to formally punch its ticket to the postseason and reach the 100-point plateau at Amalie Arena.

With two first-period goals and an empty-netter late, T.J. Oshie scored a hat trick. Nicklas Backstrom had a four-assist performance.

“I think the way we approach every game feels like a must-win,” Oshie said. “Through to core and the coaching staff and the rest of the guys, we’ve done a pretty good job of getting that winning feeling and a winning attitude in here, so every time we come to the rink, whether we just got off a little bit of a slump or whether we’re playing great hockey, we’re expecting to win and it feels like a must-win.”

With the game tied at 2 entering the third period, the Capitals pulled away from the Lightning thanks to a pair of shots from defensemen. Tampa Bay’s Jonathan Drouin was called for interference a minute into the period, and just after the Capitals’ power play expired, forward Andre Burakovsky set up a one-timer for Matt Niskanen that was tipped in by forward Justin Williams in front.

John Carlson’s goal, a baseball swing at a bouncing puck, gave Washington a two-goal lead 5:30 into the period. With the Lightning net empty in the game’s final minutes, Tampa Bay’s Nikita Kucherov scored his second goal to make it a one-goal deficit late, but Oshie’s third goal followed shortly after and the Capitals held on for a win they very much needed.

“We were emotionally engaged, we were doing the right things and shooting the puck,” Trotz said. “Got a good result.”

When asked why he considered this a must-win for Washington, Trotz pointed to the team’s 4-5-1 record in the past 10 games and the fact that the once highflying offense has been in a slump. He said that was “not acceptable.” Saturday’s game was just the fourth time the team has scored more than two goals in the past 15 games, and it was the first time in that span the Capitals have tallied five goals.

To Trotz’s point, because the top of the Metropolitan Division standings are so congested, a loss to the Lightning could have caused the Capitals to slide from first to third place in the division by the end of the weekend.

Saturday’s game in Tampa also marked the first time the team fielded a completely healthy lineup since the trade-deadline acquisition of defenseman Kevin Shattenkirk. Burakovsky, who missed the past 15 games, played for the first time since injuring his hand on Feb. 9. That complete lineup didn’t last long as Marcus Johansson skated just 2:53 before missing the rest of the game with a stomach illness.

Burakovsky had his first full-contact practice with the team on Friday. His right hand still had a wrap around it, and he admitted it still aches. But Burakovsky was reassured by a doctor that his hand couldn’t get any worse, and he said it didn’t hurt so bad when he was shooting. On Saturday night, his solution seemed to be to shoot often, recording five shots on goal in the second period alone.

“I had so many good chances where I definitely should have scored,” Burakovsky said. “I mean, I’m still a little bit rusty with my shooting, but it’s going to come back.”

While Trotz may have called this a must-win game for Washington, Tampa Bay had more at stake, just a point out of the second wild-card position entering the matchup. The desperation to make the playoffs showed in the Lightning’s response to the Capitals’ 2-0 lead thanks to Oshie’s first two goals. Kucherov capitalized on the power play, and 16 seconds later, Tampa Bay’s Alex Killorn tied the game with an improbable shot while falling down.

But by the time the game was over, hats rained down onto the ice for Oshie’s third goal of the game. His first came on the power play, and that established a new career high for him with 27 goals this season. He extended that 11:52 into the game when he one-timed a slick feed from Alex Ovechkin on a two-on-one. Oshie’s 28th goal of the season moved him into a tie with Ovechkin for the team lead. With his 29th, he moved into sole possession of that title.

“More importantly, we’re getting our game back to where we want it to be,” Oshie said. “It feels good.”