WILMINGTON, Mass. — Bruins forward Brad Marchand seems to have the answer as to why the Boston-Washington series has been so tight.

Really, it’s pretty simple.

“Both teams are just really resilient and I think both teams have a lot of character,” Marchand said after practice Tuesday. “And when you have guys like that in the room and on the ice, a little momentum swing won’t affect guys and they can bounce back fairly quickly from it.”

Indeed, this Eastern Conference, first-round pairing has been historically close. Not only is it knotted 3-3, it is the first NHL series to ever have its first six games decided by one goal.

“That just seems,” Marchand said, “to be the case so far.”

Game 7 is tonight at TD Garden.

The Bruins staved off elimination with a 4-3 overtime win in Game 6 Sunday. They won two of the three games played in Washington. But the Capitals have also won two road games in the series, and they also triumphed in both visits to Boston during the regular season.

So, who knows, maybe the hostile environment plays to the Capitals’ strengths.

“Obviously, Boston’s a tough rink to play in, but I think it suits our team well because it brings us down to a level where we don’t try to do too much,” Washington goaltender Braden Holtby said. “We don’t try to be too fancy. I think we’ve been guilty of that in front of our home crowd a bit, letting our emotions get to us with the noise of the crowd and whatnot. And I think playing on the road really helps us.”

The Capitals are staying level-headed though, knowing that past success in Boston might not continue in a Game 7 atmosphere.

“You don’t think about it too much. You hear about it and you recognize that, but it’s not something where we’ll say, ‘Oh, we’re gonna beat them because we’ve beat them before on their rink,’ ” Washington defenseman Karl Alzner said. “Every game is going to be different. We just really have to remember the simple things and play that simple game.

“It’s always nice if you can win a Game 7, 4-1, 5-1, but you’ve got to be realistic and tell yourself that it’s going to be a tight game and you’ve got to battle right to the end and don’t worry about wanting to get a lead and just coast.”

Boston knows the Garden might not have a large impact on a Game 7. Although the Bruins won two Game 7s at home during their run to the Stanley Cup championship last year, their ultimate victory came on Vancouver’s ice in Game 7 of the Cup finals.

Without question, though, the Bruins will draw on that win over the Canucks.

“It matters a bit. We know we have to battle for 60 minutes right down to the last buzzer,” Marchand said. “But in Game 7, anything can happen. It’s usually a lucky bounce or a minor mistake that will decide the game.

“So we have to be prepared to play our best game yet in this series.”

Boston center Patrice Bergeron should help. He has had two days to rest his undisclosed injury. The Selke Trophy finalist was injured in the second period of Game 5. He returned to that game and then played in Game 6, but the league’s second-place finisher in faceoff percentage during the regular season took only one draw.

Although Bergeron did not practice Tuesday, he’s expected to play tonight. When asked if he had any concerns of missing Bergeron for Game 7, Bruins Coach Claude Julien said: “Not at all.”

TUESDAY’S GAME

DEVILS 3, PANTHERS 2: Travis Zajac scored at 5:39 of overtime and host New Jersey avoided elimination and sent yet another Eastern Conference first-round series to a seventh game by beating Florida.

Steve Bernier and Ilya Kovalchuk also scored and Martin Brodeur made 14 saves for New Jersey, which squandered a two-goal lead and had fans dreading another first-round playoff exit until Zajac scored from the right circle.

The shot beat Scott Clemmensen to the lower corner and set off a mob scene on the ice.

Clemmensen was outstanding, stopping 39 shots in an emergency start for the injured Jose Theodore. Kris Versteeg and Sean Bergenheim tallied for Florida, which was looking for its first series win since 1996.

Game 7 will be played in Sunrise, Fla., on Thursday.

Two other series in the conference are also headed to Game 7s. Washington will be at second-seeded Boston tonight and Ottawa will be at the top-seeded Rangers on Thursday.