Brenden Dillon and Dougie Hamilton also scored for the Devils (14-7-2), who have won four of five. Jake Allen made 23 saves and recorded his 200th NHL win.
“Didn’t love a lot about our game, quite honestly,” Devils coach Sheldon Keefe said. “But I thought we played smart enough defensively to limit a lot of what their strengths are defensively. Because of that we only need three [goals].”
Matt Roy and Connor McMichael scored for the Capitals (13-6-1), who have lost consecutive games for the first time this season. Charlie Lindgren made 30 saves.
“It’s frustrating to lose back-to-back,” Lindgren said. “I thought we did a lot of good things tonight, had some good [offensive]-zone time, had some good chances late. Their goalie made some big saves, and we lost 3-2.”
Roy gave the Capitals a 1-0 lead at 13:52 of the first period, scoring on a high wrist shot from the right point. It was the first goal as a Capital for Roy, who was signed as a free agent on July 1 and missed 10 games with a lower-body injury in the first month of the season.
Tatar tied it 1-1 with a power-play goal at 16:31. Erik Haula received a backdoor pass from Luke Hughes, and his shot trickled past Lindgren and came to a stop on the goal line before Tatar knocked it in.
“It was a great play by Luke and a good shot by Erik,” Tatar said. “I wasn’t sure really how he saved it, but I saw it trickling in, and then it stopped. I was just sprinting there to get the cookie. It was fortunate.”