Vancouver tied it 1-1 at 6:36 of the second period when Liam Ohgren tried to center a pass to Zeev Buium off a rush, but the puck went off the skate of Anaheim defenseman Tristan Luneau and into his own net.
The Ducks regained the lead 30 seconds later after a long rebound came to LaCombe in the right circle. LaCombe quickly fed Malott in front of the crease and he scored with the tip-in to make it 2-1 at 7:06.
Anaheim was on a power play when Beckett Sennecke deflected a shot by Cutter Gauthier for a 3-1 lead at 15:44.
Merilainen gave up another long rebound that went off Buium and back into the crease, where Carlsson pushed it across the goal line for a 4-1 lead at 18:24.
Boeser scored when the puck rebounded off his body and into the Anaheim net to cut it to 4-2 at 11:40 of the third. Ducks forward Alex Killorn attempted to swat the puck away from the net but it instead hit off of Boeser's chest and got past Dostal.
"That was a terrible loss," Quenneville said. "You know, 5-2 and we're in a pretty good spot. Not a pretty good spot, we should have had to seal the win. I think we do some things that come back to haunt us after a night like tonight. Giving them some life with some plays that we make with possession and, all of a sudden, they go the other way, or it's in our net.
"We carelessly make plays senselessly. I think that's where we've got to be smarter. We've got to play smarter as a team, and we've got to be doing the little things right, especially at those times of the game, where they've got to manufacture."