Silence swept TD Garden as Troy Brouwer’s shot whipped past Tim Thomas and into the Boston Bruins’ net to give the Washington Capitals a lead with less than 90 seconds remaining in regulation of Saturday’s Game 5. This wasn’t the way many thought this series would go, least of all the dumbfounded, sold-out crowd.

But after five gritty, nail-bitingly close contests in this first-round NHL playoff series, Washington has pushed the defending Stanley Cup champion Bruins to the brink of elimination.

Brouwer’s goal stood as the game-winner in a 4-3 Capitals triumph and three-games-to-two edge in the series. Washington will return home to Verizon Center for Game 6 at 3 p.m. Sunday with the chance to clinch a victory in this Eastern Conference quarterfinal series and its third trip to the second round in five years.

“We’re in a great spot right now. We’ve battled extremely hard to put ourselves here,” Karl Alzner said. “I bet a lot of people probably wouldn’t have thought we’d be in this position. It’s just from desperate hockey. We’re working hard and we’re getting a lot of good breaks and guys are scoring when we need to score goals.”

Washington has never knocked out a defending champion from the postseason. The Capitals know a decisive fourth victory will be the toughest one to obtain against an experienced Bruins squad.

Which is why, Capitals players insisted, the message must stay the same: Focus on the details of their defensive system, renew dedication to clearing the puck from in front of their own net, block shots and ensure that the forecheck punishes their foes. In short, do all the things that got them to this point.

“You’ve got to calm your nerves right away,” Brouwer said of how the Capitals must approach Game 6. “You know that it’s going to be a close game, it’s going to be a very desperate game. Teams are going to take chances if they’ve got their backs against the wall and you just got to fall back on our systems and your rocks that you’ve been using all season long.”

Boston has stared down elimination before. The Bruins faced this exact situation last spring on its title run — in the Stanley Cup finals against Vancouver.

“I hope we can rely on the experience from last year,” Boston defenseman Dennis Seidenberg said. “We have to look at ourselves. We have to come out harder, with more energy and get emotionally involved a bit quicker than we have the first few games, and I’m sure we’re going to do that different tomorrow.”

Game 5 offered the latest example of the Capitals’ ability to stay the course in face of adversity.

Things went as well as the visitors could have imagined for the opening 35 minutes. A relentless cycle led to Alexander Semin’s third goal in as many games to put Washington ahead 1-0 at 11 minutes 16 seconds of the second period. The Capitals took advantage of hobbled Bruins defenseman Joe Corvo, who had taken a shot off his knee, and kept the play going until a point shot by Dennis Wideman left a rebound in front for Semin.

Jay Beagle scored his first career playoff goal a little more than three minutes later as his shot went off the glove of Tim Thomas (28 saves), giving the Capitals the first two-goal lead of the series for either team.

The advantage didn’t last as the Bruins forced what could have been the biggest momentum swing of the series. Seidenberg and Brad Marchand scored 28 seconds apart with less than three minutes left in the second to even the score at 2. With the game suddenly tied and Boston whipped into a frenzy, the Capitals took refuge in the intermission and gathered their composure once more.

“To our benefit, we went into a break and we had an intermission to regroup and come out hard. I don’t think we hung our heads at all after those two goals,” said goaltender Braden Holtby, who finished with 34 saves. “We knew that they’re a good team and they’re capable of it. It wasn’t a huge shock. We just wanted to rebound and we did.”

Early in the third period, veteran winger Mike Knuble put Washington ahead once more. Fellow fourth-liner Joel Ward put a shot on net and the rebound popped directly to Knuble in the left faceoff circle, where he fired into a wide-open cage to make it 3-2 Capitals.

Bruins defenseman Johnny Boychuk tied the contest once more at 3 when his blast from the point on the power play — Boston’s first power-play goal of the series — beat Holtby 8:47 into the third. Still, the Capitals refused to grow flustered or deviate from the principles that helped them reach that point. Brouwer’s tally would be the reward for maintaining composure.

That foundation is what Washington will need to lean on again, if it is to close out this series in six games.

“The one thing we don’t want to do is come back to Boston,” Beagle said. “We’ve got an opportunity here to go home and close this out, they’re going to come out hard and we’re going to see the best we’ve seen from them all year. It’s going to be a game.”