WASHINGTON — Fans were optimistic ahead of the Washington Capitals Thursday night playoff opener against the Philadelphia Flyers, and the team vindicated them with a 2-0 shutout on the back of a stellar penalty kill and 19 saves by goalie Braden Holtby.

The Capitals took three unanswered penalties in a closely contested first period alone, but each time, their penalty kill unit, which was ranked second in the NHL during the regular season, managed to keep the Flyers off the scoreboard.

As the game wore on, the Flyers started racking up penalties of their own, culminating in a penalty-heavy third period that included a 10-minute game misconduct for Ryan White and a five-minute fighting penalty after a Wayne Simmonds-Tom Wilson bout. At game’s end, the Flyers had 35 collective penalty minutes to the Capitals’ 21.

“I think game ones always are emotional,” said Washington coach Barry Trotz after the game. “It’s sort of a new beginning when you start a new series… I think we’ve got to be disciplined, can’t react to stuff and got to play through it.”

The heated game one didn’t worry the Caps’ bench boss going forward.

“As the series goes on, we’ll settle down. I don’t think it’ll escalate. We understand we have to play with discipline,” Trotz said.

He highlighted the penalty kill and Holbty working together as a reason for Washington’s defensive success.

“Your goaltender is your best penalty killer and he was good. The penalty kill was good,” Trotz said. But he also said he was pleased with the Capitals’ power play, which scored the Capitals first goal courtesy of defenseman John Carlson.

“We put a couple wrinkles in there,” Trotz said. “We’ve got a few more.”