Avalanche center Nathan MacKinnon did not play because of a lower-body injury. Bednar said MacKinnon is "banged up a little bit" and did not want to risk him aggravating the injury so close to the playoffs.
Cal Petersen made 34 saves for Los Angeles (21-25-6), which was eliminated from playoff contention Friday.
The teams will play again here Saturday.
"It was a real good game for us to play and a great game for us to evaluate where individuals are," Kings coach Todd McLellan said. "We've got a long, long way to go to close the gap, but I think it's better for us to play in these games right now than to have some token games against some teams that maybe aren't in the playoffs."
Tyson Jost gave the Avalanche a 2-1 lead at 2:56 of the second period when his shot from the left face-off circle went in off Petersen's pads. Jost was the center on the first line in place of MacKinnon.
Makar made it 3-1 at 10:02 when Petersen was screened and late to react to his wrist shot.
"I don't think anybody can fill Nate's role, obviously, but collectively as a group everybody just has to step up," Makar said. "I think a lot of guys stepped up tonight, and defensively, I think we played a little bit better game. It's just going to be improving from there."
Alex Newhook, a forward selected by Colorado with the No. 16 pick in the 2019 NHL Draft, had the secondary assist on Makar's goal for his first NHL point in his second game.
Gabriel Vilardi cut it to 3-2 at 17:26 of the third period.