BOSTON -- Matt Niskanen scored 2:36 into overtime, Philipp Grubauer made 33 saves, and the Washington Capitals started a four-game road trip with a 2-1 win against the Boston Bruins at TD Garden on Saturday.
Niskanen beat Bruins goaltender Tuukka Rask with a slap shot from the high slot after a pass from Andre Burakovsky.
"I just got on the ice, and a lot of times that we do 3-on-3 like that, we start interchanging and crisscrossing, trying to free up some space, and that's kind of what happened," Niskanen said. "[Burakovsky] did a good job getting the interception there. I had just enough room to get a slapper off from up top, and I don't know if it went off their defender's stick or not but somehow it found its way in."
Washington (48-13-4) became the first team in the NHL to reach 100 points this season. The Capitals, who have 17 games remaining, are the only team that hasn't lost consecutive games in regulation; they lost 3-2 to the New York Rangers at Verizon Center on Friday.
Video: WSH@BOS: Alzner deflects the puck home
Karl Alzner scored for the Capitals, who have defeated the Bruins six straight times since March 29, 2014.
Patrice Bergeron scored in his third straight game, and Rask made 28 saves for Boston (36-23-7). The Bruins, who are 15-16-4 at home, finished their four-game homestand 2-1-1, including a win against the Western Conference-leading Chicago Blackhawks.
"I think we had a pretty good week at home," Bruins forward Brad Marchand said. "It's something that we have to continue to work on, being a little bit better at home. But it is something we are focusing on and hopefully we continue to get better."
An excellent keep-in by Kevan Miller batting down the puck at the Washington blue line helped set up Bergeron's first-period goal. Miller fed it to Lee Stempniak, who found Brad Marchand down low. Marchand fed Bergeron in front at 7:11 for a 1-0 lead.
Video: WSH@BOS: Bergeron opens the scoring
Bergeron moved past Terry O'Reilly into eighth place on the Bruins' all-time scoring list with 607 points.
Boston thought it had another goal when Torey Krug beat Grubauer at 3:17 of the second period. But Capitals coach Barry Trotz challenged that the Bruins broke into the zone offsides and the goal was nullified when it was ruled Loui Eriksson crossed the blue line before the puck.
"If it's offside, it's not a goal, so I mean it's frustrating," said Krug, who has a 40-game goal drought. "I haven't scored in a while, but that's a good test for your character and trying to respond and still having faith. It's, like I said, right time, right place, it'll happen."
Video: WSH@BOS: Grubauer denies Spooner's power-play chance
Alex Ovechkin received a boarding major at 5:36 for a hit on Miller, who left the game grabbing his right shoulder. With Ovechkin in the penalty box and Dmitry Orlov later called for interference, the Bruins had a 5-on-3 for 1:50. Grubauer made several point-blank saves and Bergeron hit the post.
"The penalty kill was really, really good tonight, I thought, and we go down two men then for almost a full two minutes ... to be honest we didn't do a whole lot to deter much of the stuff," Niskanen said. "I guess most of their shots were from kind of down around the sides of the net ... [Grubauer] stood tall. I think they hit a couple posts, and you need to get a little bit lucky in those situations when they have that much time, and they are talented too."
The Capitals took advantage of some sloppy play by the Bruins down low in the defensive zone and Alzner tied it 1-1 at 13:08 with a redirect in front after a feed from Backstrom.
The Capitals outshot Boston 10-4 in the third period but the game remained tied.
Video: Niskanen's OT winner lifts Capitals past Bruins, 2-1