Mikko Rantanen and Andre Burakovsky scored, and Philipp Grubauer made 35 saves for the Avalanche (33-17-6), who won their previous five games. They are second in the Central Division, two points behind the St. Louis Blues.
"Real good team in Washington, they have something to say about it," Colorado coach Jared Bednar said. "They come at us in the third, we do a job, survive for a while, but we didn't win enough battles. We won some races, but we didn't win enough battles. We needed more jam, more jam at the end of the game, more desire to win the game."
The Avalanche took a 1-0 lead at 2:54 of the first period when Nathan MacKinnon passed across to Burakovsky in the right face-off circle on a 2-on-1. Rantanen made it 2-0 at 16:05 on a power play when he took a drop pass from MacKinnon and shot short-side from the right circle.
"I think it was not acceptable," said Backstrom, who spoke to the Capitals during the first intermission. "The way we've been playing lately too, it's not acceptable. We've been talking about details and stuff like that, and we're going out in the first period and we're not even there, and I think in this League you have to be aware of what you're doing out there at all times. I think we bounced back pretty good after that and worked ourselves into the game."
The Capitals closed to 2-1 at 11:37 of the second period when Jakub Vrana passed through the slot to Backstrom for a redirection at the left post.
Washington killed a one-minute Colorado two-man advantage that started with 3:13 left in the period.
"The special teams, the 5-on-3, was huge," Reirden said. "Obviously your goaltender has to be solid in these situations. But if you can kill off on a 5-on-3, somehow the numbers tilt in your favor heavily, even if you're behind in a game like that. That was a big turning point in the game."
Wilson tied it 2-2 at 12:48 of the third period on a power play, tipping John Carlson's shot from the right point after Burakovsky was penalized for high-sticking Oshie.
"They scored two (third-period) goals and capitalized on a stupid penalty that I took," said Burakovsky, who played for the Capitals from 2014-19. "They won more battles than we did in the third and I think we have to battle through it and find a way."