"This was an emotional one for us," Landeskog said. "We wanted to bounce back, and every time you go into a break like this the last game you play is also fresh in everyone's minds, and you want to build off of that and feel good about yourself during the break. We wanted to make sure that we played as good as we could."
MacKinnon one-timed a pass from Mikhail Grigorenko past Jonathan Quick five seconds after a Colorado power play expired, to complete a comeback from 2-0 and 3-2 deficits. Landeskog's second goal was an easy conversion from Tyson Barrie on the power play at 7:38 that tied the game 3-3.
The two-goal flurry gave the Avalanche (27-22-3) a win one night after a 6-1 loss at the San Jose Sharks.
"Good teams throw those away," forward Matt Duchene said of the loss to the Sharks. "You can't dwell on it. You can't bring it into the rink. You learn the lessons and you go from there."
The Kings (30-16-3), who outshot Colorado 38-19, lost for the fourth time this season when leading after two periods (18-4-0).
"I think our penalty-killing and our play in general was a little slow tonight," forward Dwight King said. "They move the puck pretty well, but … it's not like us."
King salvaged a forgettable second-period start for the Kings with a tap-in goal off a playmaker's pass from Jordan Nolan at 15:13, putting Los Angeles ahead 3-2.
It came after the Avalanche erased a 2-0 deficit on goals by Duchene and Landeskog. Duchene beat Quick with a shot from the right circle 42 seconds into the second for his 23rd goal, and Landeskog converted a huge rebound left by Quick on Blake Comeau's shot at 7:10.