MacKinnon had a goal and an assist for the Avalanche (28-19-5), who have lost three of four (1-1-2) and visit the Minnesota Wild on Wednesday. Alexandar Georgiev made 32 saves.
"The goals that we gave up weren't necessarily that they were on a big push," Colorado coach Jared Bednar said. "We just made some mistakes and gave up some chances. So, we'll look at it, review it, show it, and learn from it. We forced them into some mistakes too and had some really good chances.
"Tonight, we did a better job of scoring on some of our chances, and I think it was a more complete game tonight."
Artturi Lehkonen gave the Avalanche a 1-0 lead 50 seconds into the first period when his wrist shot from the left face-off dot beat Vasilevskiy to the far side.
"You never want that," Stamkos said. "[Vasilevskiy] gives us a chance to win every night. The first two periods, they were better than us, and he kept us in it. The third period, I thought we were the better team, and we're able to get a point and then anything can happen in OT and in the shootout."