Max Pacioretty and Aliaksei Protas scored for the Capitals (36-30-11), who are 0-4-2 in their past six and sit one point behind the Detroit Red Wings for the second wild card into the Stanley Cup Playoffs from the Eastern Conference. Lindgren made 18 saves.
“We just need to play better,” Capitals defenseman John Carlson said. “I don't think we're firing on all cylinders like we were there for a little bit. Too many turnovers, too many mistakes that we shouldn't be making and giving teams more life than they deserve or need.”
Pacioretty gave the Capitals a 1-0 lead at 4:43 of the first period with a one-timer from the bottom of the right face-off circle off a touch pass from Hendrix Lapierre.
Kastelic tied it 1-1 at 5:40 of the second period. He took a pass from Jakob Chychrun in the right circle, drove to the net and lifted a backhand over Lindgren’s glove in front.
“It's just been a little tough, but we'll put our head down, keep working,” Lapierre said. “We know we believe in this group. I think that's the most important thing, everyone still believes, and we'll find a way through this."
Protas put the Capitals ahead 2-1 at 17:10, scoring in front on the rebound of Trevor van Riemsdyk’s wrist shot from the left point.
“There’s some good stretches of that game that we play at a decently high level, it’s just sustaining that and being consistent with it," Capitals coach Spencer Carbery said. "It’s a real struggle for us right now to do it for 60 minutes.”