As the Boston Bruins started to slowly inch their way back into the game Monday night, a familiar story for the Washington Capitals started to unfold.

For the second straight game, a depleted Capitals lineup got off to a strong start against the Bruins, inserting life into empty Capital One Arena. The goal horn blared three times for the home team, but then, just as it was Saturday night against the same opponent, the Capitals’ three-goal advantage was wiped away.

And while Washington was able to prevail in overtime Saturday, the Bruins made sure to finish the job Monday, tallying five unanswered goals to beat the Capitals, 5-3, and hand them their first regulation loss of the season.

“I don’t think it’s just one particular thing,” Capitals defenseman John Carlson said. “It’s kind of a lot of things . . . just little things all over the ice. We didn’t play very well tonight. I mean, last game I thought we had a lot better effort toward the end of the game than we did tonight.”

Brandon Carlo scored the game-winner for the Bruins, beating Capitals rookie goaltender Vitek Vanecek from the right faceoff circle to give Boston its first lead with 2:37 left. Brad Marchand scored an empty-net goal with 1:26 to play.

Washington is now 6-1-3, but it let two points slip away in the final game of a six-game homestand.

“I don’t think we’re too concerned,” Carlson said. “After every game, we have a clear, concise message of what we did well, and let’s try to do more of that than what we did poorly and try to clean up those areas.”

The Capitals got off to a strong start Monday when longtime former Bruins captain Zdeno Chara struck first against his old team 13:26 into the first period and forward Daniel Sprong made it 2-0 just 11 seconds later. After Chara spent 14 years with the Bruins, Monday’s goal was his first against Boston since April 11, 2006, when he played for the Ottawa Senators.

Both Chara and Sprong have two goals this season, and the Capitals’ depth continues to be an asset. Washington leads the NHL with 17 players having notched at least one goal.

“The first period we came out strong,” Sprong said. “Last game against Boston, [the Bruins] kind of dominated us in the first. This game we came out hard in the first; we just didn’t finish the full 60 minutes.”

Washington had almost scored another goal midway through the first period, but it was overturned after Boston challenged the play for being offside. Carl Hagelin appeared to get his first tally with a deflection of Carlson’s shot, but instead it was determined Garnet Hathaway was ahead of the play.

Carlson gave the Capitals a 3-0 lead at 8:35 of the second period with a wrister on the power play for his fourth goal of the season. Jakub Vrana, who was moved down to the fourth line, was awarded the primary assist on the play and finished with two assists, responding well to his demotion.

From there, however, the Capitals’ night started to turn.

Vanecek, who made his seventh straight start, finished with 28 saves but struggled after stopping all eight Boston shots on goal in the first period.

Bruins forward David Pastrnak cut into the Capitals’ lead with a one-timer from beyond the faceoff circles at 12:37 of the second. When Pastrnak curled into the slot and beat Vanecek again 6:08 into the third, Washington’s advantage was down to one.

Washington’s Tom Wilson and Boston’s Trent Frederic dropped the gloves 8:49 into the third period, and the momentum swung further in the Bruins’ favor. It was Wilson’s first fighting major of the year.

“Sometimes you need a spark,” Frederic said. “Both games, the opportunity presented itself, but it takes two to do it.”

Craig Smith tied the score at 3 when he buried a one-timer off a great feed from Jeremy Lauzon at 13:07 of the third. Carlo’s goal broke the tie.

“The third period and the goals they scored were — I don’t like the fact that we weren’t attacking as much,” Capitals Coach Peter Laviolette said. “The three goals and the manner in which they happened, it seemed like on each instance we lost coverage, we lost a man for different reasons.”

The Capitals were without four players Monday: centers Evgeny Kuznetsov and Lars Eller, defenseman Justin Schultz and goaltender Ilya Samsonov.

Samsonov and Kuznetsov have yet to be cleared to come off the NHL’s covid-19 protocol list. Captain Alex Ovechkin and defenseman Dmitry Orlov, who also went on the list Jan. 20, were cleared to play Saturday. Ovechkin played in that game but Orlov returned Monday, finishing with 15:24 of ice time.

Eller missed his third straight game because of an upper-body injury. He has been back on the ice the past couple of days skating in a noncontact jersey, but he is still listed as day-to-day. Schultz missed his second game after he took a puck to the face against the New York Islanders on Thursday. Schultz has not resumed skating, and he is also still listed as day-to-day.

Forward Conor Sheary added to the Capitals’ injury woes Monday when he limped down the tunnel to the dressing room after a collision with Boston’s Sean Kuraly at the blue line just before Carlo’s winning goal. He is also considered day-to-day with a lower-body injury.

Washington visits the New York Rangers on Thursday night.

“Overall, we showed we have some character,” Vrana said of the Capitals’ first 10 games. “We showed we have a strong group of players that goes out there and work hard for every inch out there, try to win every game. Basically tonight didn’t work out our way. But you have to turn the page and learn the mistakes and [focus] on the next game ahead of us. Just keep rolling here and [try] to get back on a winning track.”