Capitals center Nicklas Backstrom scores the game’s only goal in the second period. With the win, Washington advanced to the second round of the Stanley Cup playoffs. (Ton iL. Sandys/The Washington Post)

For how scarce goal celebrations had been lately, this one needed to be memorable. Alex Ovechkin’s feet joyfully kicked up at the sight of a puck catching the net, a sort of “running man” on ice. Those skates eventually moved toward Nicklas Backstrom, and Ovechkin simultaneously embraced him with John Carlson.

To that point, Philadelphia Flyers goaltender Michal Neuvirth had stopped 72 consecutive shots by the Washington Capitals, but with the end of the scoring drought came the conclusion of a series. The Capitals beat the Flyers, 1-0, in Game 6 at Wells Fargo Center to advance to the second round of the Stanley Cup playoffs.

Goaltender Braden Holtby shut out the Flyers for a second time this series, making 26 saves. The six goals the Capitals allowed in six games were a franchise low in a best-of-seven series. Washington’s next opponent will be the Pittsburgh Penguins, who beat the New York Rangers in five games.

“We feel like we accomplished something big here,” T.J. Oshie said. “We know there’s still a long ways to go, but Philly gave us a great series, and they played hard. We’re tired in here. We had to work for it, so it was fun, a fun way to win.”

Backstrom’s goal in the second period that sent Ovechkin’s feet skyward broke a drought that lasted more than 106 minutes. Fittingly, it was a phantom call on Backstrom that started the game-changing sequence. He had been dealt a double-minor for high-sticking Philadelphia’s Ryan White, but video replays showed that it was actually Flyers forward Chris VandeVelde’s stick that caused White to bleed.

“It was a tough call,” Backstrom said with a laugh. “. . . It happens. I was pretty nervous in there.”

Said Justin Williams: “The playoffs are all about not letting anything bother you. On the bench, we said, ‘It’s a penalty call. It’s not going to be rescinded.’ You’ve got to kill it.”

Just five seconds into a four-minute power play for Philadelphia, Capitals defenseman Matt Niskanen was whistled for hooking, giving the Flyers two minutes of five-on-three hockey. Washington’s penalty kill was ranked second in the league during the regular season, and it has been especially strong in this series, allowing just one power-play goal. It killed the five-on-three, and a holding-the-stick penalty on White negated the last 1 minute 30 seconds of Philadelphia’s power play.

“If we don’t get through that, this building probably explodes,” Capitals Coach Barry Trotz said. “We were able to get through that, and to me, once we got through that, I felt that we were going to find a way to win the hockey game.”

Less than thirty seconds after Backstrom sprung out of the penalty box, Ovechkin muscled his way through two Flyers, protecting the puck at the blue line and creating a two-on-one. Ovechkin dished the puck to Marcus Johansson between the circles, and he set up the one-timer by Backstrom on the right side.

“He makes the whole play, I think,” Backstrom said of Ovechkin.

Washington Capitals reporter Isabelle Khurshudyan explains how the team has changed in the past year and how that could affect its playoff chances. (Thomas Johnson/The Washington Post)

“An unbelievable shot,” Neuvirth said of Backstrom’s goal. “I don’t think I could have stopped it.”

That goal ended a frustrating spell for the Capitals. They had no trouble scoring on goaltender Steve Mason, winning the first three games of the series, but a goaltending switch before Game 4 led to two straight losses. A desperate Philadelphia team with its season at stake played with more urgency than Washington in Game 4. The Capitals then looked snake-bitten in Game 5, launching a whopping 44 shots at Neuvirth only to be shut out.

The 2-0 loss at Verizon Center had the Capitals suddenly looking at a Game 6 on the road when the series seemed poised to end much sooner. Trotz blamed the “hockey gods” for the Game 5 result, karma catching the team for an uninspired effort in Game 4. He also figured that if the Capitals kept generating that many scoring chances, the goals would inevitably come.

“Coming into this series, I probably looked at it that it was going to be a long series,” Trotz said. “It wasn’t going to be four-and-out. When we got to 3-0, we were a little surprised ourselves. I think it finished up the way we expected it to be.”

Talks of past playoff collapses — like surrendering a 3-1 series lead to the Rangers last season — were inevitably brought up, and the Capitals brushed them off. Backstrom said he was looking forward. Defenseman Karl Alzner said this team didn’t have any postseason history because it was this particular group’s first go at it together.

A Game 7 would have only intensified a sense of doom and deja vu in Washington. A Game 6 win in Philadelphia showed a team taking an encouraging step to making its own history. It’s fitting that a path to exorcising playoff demons and getting to the conference finals for a first time with Ovechkin will mean knocking off the rival Penguins next.

“We’re going to enjoy this tonight,” Williams said. “We’ll talk about Pittsburgh another time.”