MacKinnon scored 4:43 into overtime, and the Avalanche beat the New York Islanders 2-1 on Friday night for their first win at home in more than seven weeks.
It was the Avalanche's first home win since Nov. 15. They had lost 10 of 11 overall, with their only victory in the last four weeks coming in Chicago on Dec. 23.
"Huge relief. It's tough to get out of a streak when you're losing every game at home," coach Jared Bednar said. "We weren't playing with a whole lot of confidence. Hopefully this builds some of that and we can string some wins together. It's been a long time, it's been tough."
The Islanders had not played since Dec. 31 in Winnipeg.
"I thought we played a pretty good hockey game after the break and I thought we had chances we just didn't score on them," Islanders center John Tavares said. "Obviously an unfortunate call in overtime and those are tough to kill and then an unfortunate bounce."
With Calvin De Haan off for hooking Landeskog at 3:34 of overtime, the Avalanche took control of the puck in the New York end. Greiss stopped Jarome Iginla, but MacKinnon knocked in the rebound.
"It was a long time coming," MacKinnon said. "It's been tough at home -- it's been tough in general. Wins haven't been easy to get."
Landeskog put Colorado in front 6:06 into the game and it stayed that way until Boychuk tied it on a 5-on-3 power play at 17:34 of the second.
MacKinnon ended Colorado's home futility with his 10th goal of the season.
FIRST TO LAST
Matt Nieto began the week with division-leading San Jose and finished it off with one of the worst teams in the NHL. He was claimed off waivers by Colorado.
Nieto delivered a big hit on his first shift with the Avalanche and then was awarded a penalty shot late in the first. Greiss made the glove save, but Nieto gave the struggling Avalanche a jolt after having just two assists in 16 games with the Sharks.
"I don't think this is a bad team," Nieto said. "There's a lot of talented guys in this room. A lot of young talent and it's just a matter of being able to put a couple of wins together. We can definitely do it."
Nieto finished with four shots in 17:29 of ice time.
New York C Shane Prince went to the locker room late in the second period after being checking into the boards. He returned in the third. ... Avalanche D Francois Beauchemin was scratched because of an illness. ... The Islanders recalled D Adam Pelech from the AHL but he was a healthy scratch. ... Colorado assigned G Jeremy Smith to the minors to make room for Nieto on the roster.
Islanders: Play at Arizona on Saturday night.
Avalanche: Host Anaheim on Thursday night after a five-day layoff.