MONTREAL -- The streaking Montreal Canadiens changed their coach's plans for the upcoming All-Star break.
Kostitsyn, who assisted on his brother Andrei's goal earlier in the third, scored unassisted to help Montreal extend its winning streak to four.
Canadiens coach Guy Carbonneau earned a trip to this month's All-Star Game at the Bell Centre as a result of the win.
Carbonneau, a three-time Selke Trophy winner during his 19-year playing career, willingly accepted a change in his plans for the league-wide break surrounding the Jan. 25 showcase game.
"I was going to go to Florida, lie on a beach and enjoy it," Carbonneau said. "I never had a chance as a player to go to the All-Star Game. Even if it's a game that doesn't have a lot of intensity, it will still be special."
Carbonneau beat out Capitals coach Bruce Boudreau by virtue of a higher winning percentage -- .683 to .662 -- for the final spot as an assistant on Boston coach Claude Julien's Eastern Conference staff along with Philadelphia's John Stevens.
"The story of my life," joked Boudreau, who won the Jack Adams Award as the league's top coach as a rookie last season. "You know what, I'm more interested -- quite frankly -- in the fact that Florida won. We could have gained on Carolina and stayed closer to Boston, so it was a heartbreaker to watch us lose like that but maybe we learn by our mistakes."
Tomas Plekanec scored his second goal of the game 4:31 into the third as the Canadiens scored three goals within 2:35 to twice take the lead.
"Games are fun to play and everyone was in it, our guys did a great job," Plekanec said. "We came back when they scored and that was great for us, we got on a roll and kept at it."
"I think we deserved at least a point tonight," said Alexander Ovechkin, who assisted on Nylander's goal. "I think we played great. We had great chances but we didn't score, especially in the first period. They had great chances and we had great chances."
Alexander Semin scored twice, giving the Capitals the lead both times. Semin opened the scoring in the first, and put Washington ahead 2-1 with his second of the game -- his 16th -- 13:04 into the second.
Jaroslav Halak stopped 31 shots in his fifth straight start for the Canadiens, who are 9-1-1 since a season-high three-game losing streak.
Johnson made 30 saves for Washington.
Plekanec, whose first goal was while short-handed in the first, drove a slap shot past Brent Johnson to put Montreal up 4-3.
Washington evened it at 4 when Ovechkin's shot from the left side deflected off Montreal right wing Tom Kostopoulos' stick and caromed off Nylander's skate and past Halak into the net.
Semin deflected Mike Green's point shot past Halak 7:59 in to put Washington up 1-0.
Plekanec tied it at 9:20 when he drove the right side and beat Johnson 15 seconds after Alexei Kovalev was sent off for high-sticking.
After Semin restored Washington's one-goal lead in the second, Montreal struck quickly as Lang scored 1:56 into the third to tie it at 2, followed by another power-play goal by Andrei Kostitsyn at 2:39 which put Montreal up 3-2.
- Canadiens D Yannick Weber was a healthy scratch after making his NHL debut in Thursday's 6-2 win over Toronto.
- Washington ended a seven-game winning streak Friday with a 3-0 loss to Columbus.