Tuukka Rask got the 22nd shutout of his career -- probably one of the easiest -- Gregory Campbell and Loui Eriksson scored second-period goals and the Bruins shut down the Capitals 3-0 on Thursday night.
"We did a great job of getting on them quickly and not giving them opportunities to make too many plays," Bruins coach Claude Julien said.
For the second straight night, the Capitals managed just eight shots in the first two periods, not the kind of offense they need as they try to move into the final playoff spot in the Eastern Conference.
So where do they go after being outshot 43-16 by the Bruins?
"Up. You can't get much lower than that, I guess," Capitals defenseman Karl Alzner said. "The killer instinct isn't there right now and it needs to be there because we are running out of time."
Washington is one point out of the eighth playoff spot with 18 games left.
Boston finished the scoring on Brad Marchand's empty-net goal with 1:34 left and moved one point behind Eastern Conference-leading Pittsburgh, which played at San Jose.
Rask's NHL-leading sixth shutout of the season came just five days after the Capitals beat him 4-2, also in Boston. But since then Washington is 0-3 and Boston is 3-0.
Rask was 0-3-3 against the Capitals in his career, but was rarely challenged on Thursday. Boston didn't even have to worry about Washington's power play, the second best in the NHL. No penalties were called in the game.
"You're kind of afraid of those guys when they get a power play because they've got so much firepower and they are so disciplined," Rask said.
Capitals goalie Braden Holtby played well but suffered his first loss against the Bruins after winning the first four matchups of his career.
"It was frustrating, but it's no more frustrating to me than it is to the other guys in the room," Holtby said. "A goalie can't rely on offense. You have no control over that. You control your game and what you can contribute to the team."
Washington has lost all its games since beating Boston on Saturday for its fourth straight win. It lost to Philadelphia twice, 5-4 in overtime then 6-4 on Wednesday night, before getting blanked by Boston.
"We talked about that before the game, how they're probably going to be a little tired and we need to take advantage of that," Bruins defenseman Matt Bartkowski said. "I think we did a good job of it."
Campbell gave the Bruins a 1-0 lead at 3:05 of the second period when he tipped in Patrice Bergeron's shot. Bergeron fired the puck from the top of the left circle and Campbell, standing just to the right of Holtby, deflected it in for his seventh goal of the season and fourth in four games.
Eriksson got his seventh at 8:20 after missing one game with an infected heel that he said he sustained at the Winter Olympics in Russia, where he played for Sweden. Carl Soderberg passed the puck from behind the net to Eriksson, whose short shot from the left side beat Holtby.
That was more than enough for the Bruins, who gave the Capitals little room to operate.
"They played last night," Julien said. "It was important for us to get on them physically and make them throw pucks away, and guys did a great job."
Alex Ovechkin, who leads the NHL with 44 goals, had just one shot after scoring two power-play goals on nine shots in Washington's win in Boston last Saturday. The Capitals took 31 shots in that game, while Holtby stopped 36 of the Bruins' 38 shots.
Washington D Cameron Schilling played after being recalled from Hershey of the AHL on Wednesday. ... Boston D Andrej Meszaros and Corey Potter were healthy scratches one day after being acquired. Meszaros came in a trade with Philadelphia and Potter was claimed on waivers from Edmonton. ... Mark Recchi, a forward on the Bruins team that won the 2011 Stanley Cup, dropped the ceremonial first puck. ... Rask played in his 46th game, a new season high. ... G Jaroslav Halak, obtained from Buffalo on Wednesday, did not play for Washington. ... Two spectators at TD Garden were injured when a section of protective netting behind one of the goals fell shortly after Thursday's game, according to media reports. The injuries were minor, and the two women were transported via private ambulance to Massachusetts General Hospital for evaluation, officials told The Boston Globe.
The Associated Press contributed to this report.