Alex Ovechkin scored his 42nd goal of the season, Evgeny Kuznetsov extended his point streak to 12 games (seven goals, eight assists) and Vitek Vanecek made 35 saves for the Capitals (37-20-10), who came from behind for their second win in two nights following a 4-3 shootout victory at the Buffalo Sabres on Friday.
"Well, I mean, it wasn't pretty, but it was gutsy," Washington coach Peter Laviolette said. "And to fight back in both games, that says a lot. I really liked the effort. I liked the compete, I liked the comeback. Guys just kept digging in for the win and got it done."
Jack Hughes had a goal and an assist, and Daws made 18 saves for the Devils (23-37-5), who have lost five of six.
"We battled to the end," New Jersey coach Lindy Ruff said. "We made a couple of mistakes. I thought when they made a couple of big mistakes in the second and we didn't capitalize. … Problem is, when we made a mistake it went in the back of the net."
Ovechkin made it 4-2 at 11:48 of the third period when tipped in a pass from Kuznetsov on a power play. He has scored 10 goals in his past 12 games.
"That was just a mistake by our forward covering Ovechkin," Ruff said. "He just let him alone for a second. For the most part, our [penalty] killing has been pretty good."
With the extra attacker on, Jesper Bratt scored to pull the Devils within 4-3 with 32 seconds remaining.
Hughes gave the Devils a 1-0 lead 55 seconds into the second period. Vanecek made the save against Dawson Mercer on a 2-on-1, but Yegor Sharangovich controlled the rebound and passed to Hughes, who scored on a wrist shot from the right circle.
Tom Wilson tied it 1-1 at 2:47 with his 20th goal, converting a pass across the slot from Conor Sheary. It's the third time in the NHL Wilson has scored at least 20 goals.
Damon Severson gave New Jersey a 2-1 lead at 7:17 when he deked around Anthony Mantha at the point and scored on a slap shot through traffic.
"I saw an opportunity just to try to make a move and [Mantha] bit on the fake," Severson said. "Fortunately enough, it opened up some room and then [assistant coach] Mark Recchi's always telling me I've got take more slap shots, so I took a slap shot and it went in."