Pheonix Copley made 33 saves in the Capitals’ 3-1 win over the Jets. (Nick Wass/Associated Press)

Nic Dowd could tell by the crowd’s reaction that Carl Hagelin had just stepped out of the penalty box. The noise inside Capital One Arena had gotten louder as the final seconds of the Winnipeg Jets’ power play ticked down. The puck was on Dowd’s stick and, well aware of how Hagelin’s speed can be a weapon, he backhanded a pass down the ice, placing it perfectly for Hagelin to streak right to the net and deliver the go-ahead goal.

“I think you always have a dream that it might land on your stick, and today was one of those days,” Hagelin said.

The home fans got even louder, showing appreciation for their newest winger scoring his first goal for the Washington Capitals in this building. But the applause was also for a penalty kill that was a strength for a change, rather than a liability. And at the end of the night, goaltender Pheonix Copley received an ovation of his own after he was perhaps the biggest star in the Capitals’ 3-1 win . He finished with 33 saves.

Washington has won seven straight games and owns a four-point lead on the New York Islanders atop the Metropolitan Division. New York has played one fewer game.

The Capitals took a 2-1 lead into the third period, and the Jets thought they had scored the tying goal with 10:17 left when Adam Lowry shoved the puck across the goal line. The tally was immediately waved off by an official, who announced that Copley was pushed into the net. Winnipeg challenged that there was no goaltender interference before the goal, but further video review sided with the original call on the ice, a break for Washington.

Defenseman Dmitry Orlov was called for tripping with 2:35 left, and the Jets had a six-on-four advantage when they pulled goaltender Connor Hellebuyck for an extra attacker. But Washington killed its fifth penalty, and center Lars Eller added an empty-net tally with 21 seconds remaining.

The Capitals entered the game on a roll, having gone 13-4-1 since the start of February, but after a string of games against teams unlikely to make the playoffs, the Central Division-leading Jets provided a good test of where Washington’s game really is a month before the postseason. The Capitals got off to a good start when center Nicklas Backstrom scored from the high slot with T.J. Oshie screening Hellebuyck at 4:35. Backstrom has scored in three straight games and is up to 18 goals on the season.

But after Washington controlled play early, Winnipeg responded less than two minutes later. Jack Roslovic found ­Mathieu Perreault, a former Capitals player, alone at the back door to smack in a feed and tie the score at 6:23.

The Jets got an opportunity to take the lead 14:28 into the game when Brett Connolly was escorted to the penalty box for tripping. Washington was penalized again just 26 seconds into the power play for having too many men on the ice, giving Winnipeg a two-man advantage for 1:34.

The Capitals’ shorthanded unit has improved after the trade-deadline additions of Hagelin and defenseman Nick Jensen, and they had killed six penalties in a 3-0 win against the New Jersey Devils two nights earlier. The team handled the Jets in the first period Sunday, too, thanks in large part to defenseman Matt Niskanen blocking a Patrik Laine shot with his left hand. Niskanen exited briefly but escaped injury.

“We had a few,” Niskanen said. “Laine gets another shot, and Dowd eats one in the chest there on the last penalty. Orlov takes one off the face to try to get it out of the zone. We’re getting to that time of year where you’ve got to step in front of a few more.”

The Capitals didn’t have a shot on goal for the final 8:10 of the first period, and they managed just two shots for the first 14-plus minutes of the second. Washington put Winnipeg on the power play two more times in the second period, and though the Capitals’ penalty kill entered the game ranked 22nd in the league, it kept the Jets’ fourth-ranked man-advantage in check.

Hagelin was responsible for both second-period infractions, which he atoned for after Washington killed off his cross-checking penalty. Dowd set him up for the breakaway as he was exiting the penalty box, and his second goal with the Capitals stood as the game-winning tally. Hagelin had two goals in 38 games between Pittsburgh and Los Angeles this season, a total he has equaled in eight games with the Capitals.

“It was great to see the guys bail me out,” Hagelin said. “Obviously I don’t want to be in the box for four minutes like I was, but it turned out okay. The guys did a great job, and Dowder made a great play there when I got out of the box.”

Coach Todd Reirden’s decision to start Copley in this game was initially confounding. The backup hadn’t played in two weeks, and having him face the banged-up Devils on Friday seemingly made more sense because New Jersey has struggled this season and Winnipeg has been one of the NHL’s top teams. But Reirden’s confidence in Copley paid off when he turned in one of his best performances of the season.

The Jets entered averaging 3.43 goals, fifth most in the league. The Capitals kept most of Winnipeg’s looks to the outside and limited its rebound opportunities, giving them some validation for their defensive improvement over the past month.

“It means a lot,” Backstrom said. “It’s really good for our confidence any time you can keep a team like this on the outside. They had some good chances. But it was something positive and will give us confidence going forward.”