With 102 points, Colorado moved three ahead of Chicago for second place in the Central Division.
"We keep working hard and we believe in ourselves," Avalanche coach Patrick Roy said. "I think that's one of the reason's we came back."
Cam Atkinson and Comeau scored in the second period for Columbus, which is hanging on to the second wild-card spot and eighth playoff seed in the Eastern Conference.
"You'd like to get two points but we did get one," Richards said. "And that might be a huge point. We don't know. We'll find out in a couple weeks."
Landeskog's goal in overtime and 26th of the season -- extending his career high -- banked off defenseman Jack Johnson and behind Sergei Bobrovsky, who returned after missing nearly three games with the flu and finished with 25 saves.
"It was as lucky as they come, I guess," Landeskog said.
Brad Malone and Landeskog scored 5:17 apart in the third period to draw Colorado even.
"We were down 2-0 but it didn't feel like it," Avalanche center Paul Stastny said. "We thought we'd get one goal and get back into it."
Malone scored at 9:46 with his second of the season on a seemingly innocent play. He threw the puck from deep in the left corner, and it hit Nick Foligno near the crease and went into the net.
Then Landeskog redirected a feed from smooth-skating MacKinnon that deflected off the Blue Jackets' Dalton Prout.
"For us as a team, I think we are doing the little things and certainly finding ways to win," Landeskog said.
The game was a bit of a track meet the first two periods, and Columbus broke through first.
It was a turnover by defenseman Nate Guenin behind his net that got Varlamov leaning the wrong way. Brandon Dubinsky sent a centering pass to Atkinson, who scored his 20th at 10:52.
Colorado counterattacked after each goal, but Bobrovsky stopped MacKinnon from in tight. He later stretched to make a nice toe save on a hard Stastny shot with the Avalanche revving up the pressure in the Blue Jackets' zone.
"We did some good things," Richards said. "I thought we played a good game."
Then later in the period on a quirky play, the Blue Jackets made it 2-0.
A bouncing puck on a long clear by Fedor Tyutin hopped past two Colorado defensemen and was finally settled by Comeau. He worked a high-speed give-and-go in little space with Foligno to tuck home his fourth and first since Dec. 19.
The overtime power play was the only one for the Avalanche in the game. ... Columbus played its first of eight games in 12 days to close out the regular season. ... Big Blue Jackets offseason signing RW Nathan Horton, who has mostly struggled since returning from shoulder surgery in January, missed the game with lower-body injury. Columbus LW R.J. Umberger, who has 18 goals and 33 points, was scratched for the fourth time in seven games. ... Blue Jackets C Derek MacKenzie played in his 300th career game.
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COLUMBUS, OH - APRIL 1: Cam Atkinson #13 of the Columbus Blue Jackets flips a puck past Curtis McElhinney #31 of...