MacKinnon made it 2-1 with 3:36 remaining when his dump-in from inside center ice caromed off the post and off Gillies.
"I was just trying to figure out what happened," said Gillies, who has won back-to-back starts in place of injured starter Mike Smith playing ahead of David Rittich. "I would understand if it was rolling and it bounced like that, but when a flat puck bounces up and back like that, it's confusing. Nothing you can do about it, good or bad. You just have to respond."
Monahan put Calgary up 3-1 with a power-play goal at 10:50, after MacKinnon hit the crossbar at 7:24 and Samuel Girard hit the post at 8:26. Monahan has eight points (two goal, six assists) in his past six games, and 15 points (seven goals, eight assists) in his past 13 games.
"We get one, and then in the second period it's just a matter of tying it up," Landeskog said. "You really see how quick things can turn there when we had the power play and Nate has one [hit] the crossbar and we have some other chances."
Brouwer scored 2:39 into the third period to make it 4-1, and Backlund scored on the power play, his first goal in 12 games, to give the Flames a 5-1 lead at 14:46.