Maroon scored at 12:16 to give Edmonton a 1-0 lead, putting in a rebound after Holtby made the initial save from in close on a Connor McDavid backhand.
Larsson made it 2-0 at 17:55. The Oilers defenseman took a drop pass from Ryan Nugent-Hopkins at the left boards, cut to the middle, and shot the puck past Holtby's blocker.
Smith-Pelly started the Capitals rally when he scored with 18 seconds left in the first to make it 2-1. He one-timed a cross-ice pass from Ovechkin past Talbot.
Eller tied the game 2-2 at 10:32 of the second period on a delayed penalty to Oilers defenseman Darnell Nurse. With Holtby on the bench for an extra attacker, Eller took a pass from Madison Bowey in the right face-off circle and shot the puck past Talbot.
"In the second period, we were turning pucks over in transition and it led into their offense," Maroon said. "We had too many turnovers at our blue line, and it cost us the game tonight. We had the momentum in the first, and they took it right away from us."
Kuznetsov gave the Capitals a 3-2 lead 30 seconds into the third period, tipping a centering pass from Ovechkin by Talbot.
Washington concludes a three-game, Western Canada road trip at the Calgary Flames on Sunday.
"We needed that win to just feel a little bit comfortable," Ovechkin said. "I think the guys right now are going to enjoy it. Tomorrow's another big one. I don't think we have good success this year on back-to-backs, so it's going to be a big test for us."
Kuznetsov scored at 15:56 on an outstanding individual effort to put Washington up 4-2, and Beagle scored to make it 5-2 at 19:41 with Talbot pulled for an extra attacker.
"We talked about playing the right way, and I thought we played the right way," Capitals coach Barry Trotz said. "We battled through things, and we stayed with it, which was, to me, probably the main thing. We just stayed with it even though we fell down in the first period there, when I thought we were playing well."
