Boston coach Claude Julien said his big two wingers on the top line - Lucic and Horton - set the tone for the victory by hitting early.
``I've always said, `If I'm coaching the other team and I have those two guys playing against me and they're playing at their best, I'd hate to be a defenseman on the other side,''` Julien said. ``The speed they come at you, puts guys on their heels. When we're forechecking well, we're turning the puck over.''
David Krejci added a goal and two assists, Rich Peverley had a power-play goal, and Andrew Ference scored his first of the season on the eve of his 34th birthday for the Bruins, who avenged a frustrating loss to the Capitals earlier this month.
Bruins backup goalie Anton Khudobin made 32 saves, and Lucic had a career-high three assists.
``When I came in (before the game) I knew he was feeling well,'' Horton said about the Lucic, a 6-foot-3 winger. ``I think everybody gets up, feeding off his personality. When we're putting it in the right spots, he' getting to the pucks. Guys are scared of him. He gets them.''
The Capitals knew Boston's big guys were hitting from the start.
``They have those kinds of players,'' Capitals captain Alex Ovechkin said. ``They do a good job.''
Michal Neuvirth made 34 saves for the Washington, which suffered its fourth loss in five games.
Boston blew a 3-0 lead against the Capitals in Washington before losing 4-3 in overtime on March 5 in their only other meeting this season.
The Bruins jumped ahead 1-0 on Horton's goal 14:12 into the game. Lucic raced in, collecting a pass behind the net, circled and found Horton in the slot. He one-timed a shot by Neuvirth.
They increased it to 2-0 just over 3 minutes later when Lucic beat defenseman Tomas Kundratek to a puck in the corner, out-muscled center Mike Ribeiro near the net before sending a pass in front to Krejci, who slipped a quick shot into the net.
``We shot ourselves in the foot,'' Washington winger Joey Crabb said. ``We turned it over in our own end and they capitalized on it.''
The Capitals cut it to 2-1 early in the second when Krejci's clearing pass from the side of the net caromed off Boychuk's skate and behind Khudobin. Johansson, the closest player to the puck, was credited with the goal.
With the teams skating four a side, Ference's wrister from the top of the left circle- off a pass from Horton - beat Neuvirth inside the right post, making it 3-1 at 8:02 of the second.
Peverley's goal off a scramble in front came 8 seconds into a power play early in the third.
The Bruins came out hitting from the start, turning the game a bit chippy at times. Boston appeared to have a plan of checking the Capitals nearly every time they passed or handled the puck. Washington responded later in the second, challenging the Bruins to a pair of fights.
``When we need that kind of stuff, we have to do it,'' Ovechkin said.
It was the teams' first meeting in TD Garden since Washington eliminated Boston in overtime of the seventh game during the opening round of last season's Stanley Cup playoffs.
NOTES: Krejci collected his 300th career point on Peverley's goal. ... It was Horton's first three-point game since Jan. 12, 2012. ... The Bruins had a video tribute for Capitals coach - and former Boston player - Adam Oates, congratulating him on making the Hall of Fame. He was given a standing ovation. ... Boston captain Zdeno Chara turns 36 on Monday. ... The Bruins wore green jerseys during the pregame skate in honor of St. Patrick's Day. ... The Capitals played the second game of six of seven away from home. ... Boston improved to 8-0-1 against the Southeast Division. ... It was the opener of an NHL-NBA doubleheader. The Celtics were scheduled to face Charlotte Saturday night. ... The Bruins have killed 25 straight penalties.