Fists of fury: Capitals defenseman John Erskine lands solid right in a scuffle with Boston’s Shawn Thornton on Tuesday night at Verizon Center. (Jonathan Newton/The Washington Post)

After the opening 20 minutes Tuesday night at Verizon Center, it looked as though the Washington Capitals would fall short in yet another game they had dubbed a test of their progress. But trailing the talented and tenacious Boston Bruins by three goals at the end of the first period, the Capitals refused to go quietly.

During intermission, players said Coach Adam Oates, captain Alex Ovechkin and newcomer Aaron Volpatti were among those who stressed there were still 40 winnable minutes left in regulation. It was plenty of time for the Capitals to mount a comeback if they put their minds to it.

Washington did precisely that, scoring three goals in the final two periods to force overtime. Thirty-seven seconds into the extra session, winger Eric Fehr raced up ice, split two Boston defenders and scored while falling down for the game-winner in the Capitals’ 4-3 triumph that featured contributions from some unusual suspects.

“We didn’t give up at all today,” said Fehr, who recorded a team-high three points. “I think it says a lot about our character. This team believes in ourselves a lot more than we did at the beginning of the season. We’re a pretty confident bunch right now and we’re believing in the system and that’s why it doesn’t matter who’s on which line. We’re playing together as a team and that’s why we’re able to win today.”

The Capitals viewed their first meeting with Boston since last year’s Eastern Conference quarterfinal playoff series as a measuring stick. They felt they had greatly improved in recent weeks and were eager to face a Bruins squad that won six of seven heading into the matchup.

After the first period, the challenge looked like more than Washington could handle. Brad Marchand scored on a short-handed penalty shot just 6 minutes 29 seconds into the contest to give the Bruins a 1-0 lead. Zdeno Chara and Dougie Hamilton each added a goal in the final three minutes of the first period and Washington appeared ready to fall back into sole possession of last place in the Eastern Conference standings.

“You start to think after the first period like that, same old song and dance that we’ve been in, and the guys, really we all turned it around,” said goaltender Braden Holtby, who made 30 saves but said he would have liked Hamilton’s goal back. “I think it’s probably just that everyone’s sick of being down like that.”

Earlier in the season that large of a deficit might have marked the end of the Capitals on any given night, but something in the mood and atmosphere around the team seems to have changed in recent days.

“Volpatti made a great comment. He said, ‘Boys, let’s just focus on winning the second period,’ ” forward Matt Hendricks said. “Instead of looking at the big picture, looking at being down by three, he said let’s just look at this next 20 minutes. We’re focused on winning this 20. I think we came out and did that.”

Just 5:46 into the second period, Mike Ribeiro scored to kick off the rally. Defenseman Steve Oleksy, who was making his NHL debut after being signed and recalled by the Capitals on Monday, blocked a clearing attempt by Chara at the point and swatted the puck back down into the Boston zone.

Ovechkin flagged down the puck with his stick, settled it and sent it across to Ribeiro on the left side of the net for an easy tap-in to make it 3-1.

“I think the guys felt that we’re still in the game, and you know what? It’s Boston. Nothing’s going to come easy,” Oates said. “You’re gonna just have to get on at a time, and we got one pretty quick in the second, which helped us a little.”

Roughly six minutes later rookie defenseman Tomas Kundratek, who has stepped into a significant role during Mike Green’s absence because of a groin injury, made it 3-2 when he recorded the first NHL goal of his career.

Nicklas Backstrom beat Chris Kelly on a faceoff, winning the puck back to Fehr who tapped it to the 23-year-old at the blue line. Kundratek ripped a shot that deflected off of at least one of Bruins player in front but found its way to the back of the net in order to cut Washington’s deficit to one.

The Capitals (9-11-1) made a furious push in the third period — Ovechkin barreled into the Bruins’ net three times as he searched for offensive chances and more energy. Finally with 13:55 gone in the third, Fehr fed the puck up ice to a breaking Wojtek Wolski, who likely wouldn’t have been in the lineup if Troy Brouwer wasn’t too sick to play, and the winger swatted the puck under Tuukka Rask’s pads to even the score at 3. It marked Wolski’s first goal since Feb. 1 and it couldn’t have come at a better time.

His tally sent the Capitals in to overtime and en route to the valuable, morale-boosting win.

“We don’t give up, Holts makes unbelievable saves. We just kept going and score two huge goals in the second,” Ovechkin said. “In the third we have that kind of feelings, I think, like we’re gonna come back because we was dominating them. Speed and energy was up there. . . . We beat great team right now, so it’s important points for us.”