The Capitals’ Jay Beagle (83) and T.J. Oshie (77) vie for the puck against Philadelphia’s Nick Cousins (52) and Sam Gagner during Monday’s Game 3 at the Wells Fargo Center in Philadelphia. (John McDonnell/The Washington Post)

The puck took a bounce off Steve Mason’s glove and back to the stick of Evgeny Kuznetsov. This was another inexplicable break for the Washington Capitals, and Kuznetsov graciously accepted the gift. He skated around a leaning Mason, swatted the puck in and didn’t even raise a glove in celebration.

The Capitals haven’t always been the best team in this series against the Philadelphia Flyers, but they have been the most opportunistic — and this 6-1 rout was just the latest example as Washington has built a commanding 3-0 series lead.

Monday night at Wells Fargo Center, the Capitals took advantage of their power play, errors by Mason and an undisciplined Flyers team in a game that got ugly late. It’s the first time in franchise history that Washington has a 3-0 series lead.

“It’s history for a reason,” Jason Chimera said. “We’re out to make our own history, and we want to keep going. It’s a lot different team than teams in the past.”

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)

This team had to show discipline. Mason’s glove squirting the puck back to Kuznetsov in the third period “took the wind out of our sails,” Flyers Coach Dave Hakstol said. With 12 minutes 23 seconds left, the Capitals got a four-on-three power play, and John Carlson scored on a slap shot up the middle, his third power-play goal of the series. That also marked the third power-play goal of the game.

With the Capitals then holding a 4-1 lead, the game became unhinged. Pierre-Edouard Bellemare got a major penalty for checking Dmitry Orlov from behind and a game misconduct. What essentially looked like a line brawl broke out over the hit, with Orlov down on the ice in pain. The result was two 10-minute misconducts to Radko Gudas and Ryan White. Disgruntled fans tossed the light-up wrist bands they received before the game onto the ice.

“It was a little dirty, but we all five jump and you see how we stick together and that’s kind of team piece,” Kuznetsov said. “You can see how we stick [up] for each other everywhere. If somebody wants to play like that, we’re going to get him back, for sure. No one [is] going to step back.”

Said Capitals Coach Barry Trotz: “Obviously, we pulled the game away and they weren’t interested in playing anymore. So, we ended up on the power play for the last seven or eight minutes. I just thought it wasn’t good for the game. Plain and simple. We’re on national television, and I don’t think it displays our game very well.”

Given the opportunities, Washington capitalized. Ovechkin scored his second goal of the game on the five-minute power play for Bellemare’s hit on Orlov. More fans tossed wrist bands onto the ice, and that resulted in a delay-of-game penalty on the Flyers’ bench. Wells Fargo Center public address announcer Lou Nolan called the fans throwing the wrist bands onto the ice “classless.”

“I grabbed one in my hand actually when they threw it,” Nicklas Backstrom said. “They were plastic, so nothing really too dangerous.”

A slashing penalty by Matt Read with less than four minutes left in the game led to a power-play goal by Jay Beagle, a franchise-record fifth of the game. Beagle doesn’t even typically play on the power play.

“The power play has lots of confidence,” Trotz said. “And they keep giving us lots of practice.”

The lone dark cloud on the night for the Capitals could be the loss of defenseman Brooks Orpik. The sequence started with a neutral zone hit by Daniel Winnik on Shayne Gostisbehere, with Winnik penalized for interference and Gostisbehere hobbling to the bench. He later returned to the game.

Less than a minute later, Mike Richards and Simmonds each went to the penalty box for roughing, the physicality of the game noticeably ramping up. White then checked Orpik into the boards, and Orpik crumpled to the ice, clearly shaken. He had to be helped off the ice by Carlson and head athletic trainer Greg Smith before being helped into the locker room. He did not return, and Trotz said he has an upper-body injury that will be re-evaluated Tuesday.

“We’re okay with the physical play,” Trotz said. “They’re a much different team here in Philadelphia than obviously in Washington. They came with everything. We’re okay. I think we’re a bigger team than them physically, but we’re more concerned with winning the series.”