Los Angeles has points in eight straight games (6-0-2) and the Kings pulled within a point of eighth-place Calgary with the victory. Washington dropped its second straight contest against a Western Conference foe, and the Capitals are now 3-6-1 against the West this season.
"It's a big two points for us," Los Angeles coach Terry Murray said. "To come into this building, against a great hockey club and play a pretty solid defensive game, first of all, and then to be able to score some goals, which have been hard to find for us recently."
The Kings took the lead early in the third period when Andrei Loktionov put home the rebound of a Kyle Clifford shot at 3:36 for his third of the season. Defenseman Matt Greene sent Clifford into the offensive zone with a great outlet pass, and Lokitonov -- playing in his preferred position at center after time at left wing -- beat Washington center Mathieu Perreault and defenseman Jeff Schultz to the rebound for an easy finish.
Two goals less than 90 seconds apart sealed the victory for Los Angeles. The puck was behind Washington goaltender Semyon Varlamov in the crease with a scrum of bodies in front of him, but Michal Handzus was able to find it and push it across the goal line at 12:28 of the third.
Jarrett Stoll completed a 2-on-1 with Justin Williams at 13:56 for his 16th goal of the campaign to end any doubt and send a large portion of the matinee crowd scurrying for the exits.
Alex Ovechkin had put Washington in front just 66 seconds into the contest with his 21st of the season. He collected an errant pass at his own blue line and rushed up the ice, cut inside on Drew Doughty and used the defenseman as a screen to snap a shot past Jonathan Bernier.
But that was all the offense the Caps could manage.
"We got a good start. We took the lead," Ovechkin said. "They kept pushing and pushing. They had the momentum and then the game."
Anze Kopitar leveled the score midway through the second period. Wayne Simmonds collected a pass from Kopitar and took the puck to the net. He wasn't able to muster much of a chance, but Kopitar was there to chip his rebound under the crossbar from the top of the crease.
It was Kopitar's first goal in 11 games and only his second in the past 21.
"My shoulder's gotten a little rusty because I haven't had my arms in the air for a while," Kopitar said. "I'm ready to get the rust off it and celebrate a little more."
Los Angeles is 3-0-2 at the midway point of a 10-game road trip and will face Eastern Conferece-leading Philadelphia on Sunday at Wells Fargo Arena.
"I thought it was a really good effort," Kopitar said. "We've had maybe not the best histories with the afternoon games, so to accomplish what we did today, it was huge, and now we've got to build on it and carry it over to tomorrow."
Washington needs to fix its struggles against Western Conference opponents, and the Capitals will have their chances -- the next three games are all on the road against teams from the West, beginning Monday night at Phoenix.
"If they're waiting for some switch to magically appear, it's not going to happen," Caps coach Bruce Boudreau said. "Hopefully this is as low as we get."
1 - 0 WSH
1 - 1 Tie
2 - 1 LAK
3 - 1 LAK
4 - 1 LAK
Delaying Game - Puck over glass