Nikita Kucherov, Victor Hedman, Yanni Gourde and Mikhail Sergachev also scored for the Lightning (24-6-2), and Peter Budaj made 32 saves, several in the closing minutes.
WATCH: [All Lightning vs. Avalanche highlights]
"Towards the end I was stopping a couple from getting in and our guys stopped a few blocks and took care of rebounds," Budaj said. "This was a big effort at the end because they were buzzing. They came on strong at the end, put on a lot of pressure."
The Lightning scored four goals in a 4:10 span of the second period to take a 4-0 lead, with goals from Kucherov, Stralman and Hedman coming 2:11 apart.
Trailing 5-1 after Stralman scored his fourth of the season at 2:29 of the third period, the Avalanche closed to 5-4 on goals by Landeskog at 4:58 and on the power play at 7:17, and MacKinnon's power-play goal at 9:22.
"I thought we got lazy," Lightning coach Jon Cooper said. "And for two periods we didn't give them any ice and for one period we gave them all the ice. And if you're going to give Landeskog and [Mikko] Rantanen and MacKinnon and go down the list of guys all that ice, they're going to do what they did."
Said Landeskog: "We're here to play, we're not going to be pushed around and we're not going to give up on anybody."