Washington moved one point behind the Ottawa Senators, who are in a four-way tie in points for the second wild card in the East with the Detroit Red Wings, Columbus Blue Jackets and Philadelphia Flyers.
“We can only control what we do out there for 60 minutes and we’re just trying to do everything we can to stay alive and get ourselves in,” Capitals forward Ryan Leonard said.
Rasmus Dahlin had a goal and an assist for the Sabres (46-23-8), who are 2-3-2 in their past seven.
Alex Lyon allowed three goals on five shots before he was replaced at 5:52 of the first period by Colten Ellis, who made 20 saves in relief.
Buffalo remained two points behind the Tampa Bay Lightning for first in the Atlantic Division, and tied with the Montreal Canadiens, who have played one less game.
“I think it's just we got to look ourselves in the mirror,” Dahlin said. “No one is playing their best hockey right now. So, we have a big day Monday [at the Lightning]. Get ready for the next one because we have to build our game going into the playoffs, that's for sure.”
Despite the loss, the Sabres qualified for the playoffs for the first time since 2011 when the Detroit Red Wings lost 4-1 at the New York Rangers earlier in the day, ending the longest drought in NHL history.
“It's really hard to really focus on that right now with a loss, but really proud of the group,” Buffalo forward Alex Tuch said. “It's been a long time coming. It's my fifth year here, and pretty happy this afternoon.”
The Capitals scored three goals in a 2:37 span in the opening period.
Chychrun put Washington up 1-0 at 3:15, pouncing on the rebound of an Ovechkin shot in the left face-off circle and snapping the puck past a screened Lyon to the blocker side.
Strome made it 2-0 just 20 seconds later at 3:35. Ovechkin sent a backhand pass to the front of the net and Protas fed the puck across the crease to Strome, who tapped it into an open net.
“We can’t defend as poorly as we did those first couple of goals,” Sabres coach Lindy Ruff said. “We left two guys wide open, the coverage wasn’t good and it ends up in the back of the net.”