Frank Vatrano, Alex Killorn and Trevor Zegras scored, and Ryan Strome had two assists for the Ducks (26-48-5), who had lost seven of their past eight (1-5-2).
"We play hard all the time, and we're a tough team to play against," Anaheim coach Greg Cronin said. "We've flirted with that throughout the year."
Akil Thomas scored, and Cam Talbot had 24 saves for the Kings (41-26-11), who had won three in a row and could've clinched a berth in the Stanley Cup Playoffs.
Los Angeles remained one point ahead of the Vegas Golden Knights, who have one game in hand, for third place in the Pacific Division.
"We thought it might be easy," Los Angeles interim coach Jim Hiller said. "It is never easy in the National Hockey League.”
Thomas gave the Kings a 1-0 lead at 5:50 of the first period. Trevor Lewis’ backhand shot hit the side of the net and caromed in front of the left post to Thomas, who scored on the rebound for his second goal in his fourth NHL game.
"We know they have a lot of skill and a lot of young talent, and they're playing pretty freely right now," Lewis said of the Ducks. "I thought we had a pretty good first 10 minutes, and then things kind of got away from us. We were starting to get in their game a little bit and turning pucks over. Second period we played pretty well but let them hang around, and they’ve got some skill and their goalie played really well."