"I liked the way our guys stuck with it," Bednar said. "We went after them pretty good. We got our forecheck rolling a little bit ... guys played good. It was a good team effort. The penalty kill was great again (5-for-5). We had a lot of guys chipping in."
Frolik scored at 2:41 of the second period to give the Flames a 2-0 lead after Backlund scored on a shorthanded breakaway at 14:19 of the first.
"Having a 2-0 lead, that's when you to try to put them away and then play sound defense," Calgary forward Matthew Tkachuk said. "We let them back in the game right away."
MacKinnon started the comeback when he beat Rittich to the short side from the left circle on a power play at 8:24. It was his 70th point of the season, the first time he has reached that number in his five NHL seasons.
"I felt once we score, we get confident," MacKinnon said. "We have a very positive group, a very hungry young team. I'm not surprised. We do a good job of sticking to the game plan."
Zadorov carried the puck into the left circle and beat Rittich to the far corner at 9:32 to tie the game 2-2. Barrie completed a tic-tac-toe passing play with Mikko Rantanen and MacKinnon at 12:41 for a 3-2 lead.
"It was a great play by Nate and Mikko," said Barrie, who scored from the left of the net. "Mikko made an unbelievable pass to me. I almost skated right by the net. I didn't have a great angle at it, so I was just trying to get it on net. I probably unnecessarily put it upstairs."
Duncan Siemens scored his first NHL goal into an empty net with 17 seconds to play to make it 5-2.
"It was definitely a heartwarming moment for me to see the support of the guys," said Siemens, a 24-year-old defenseman who played his 10th NHL game. "It means a lot when the guys are that excited for me. To get the first one is definitely nice. I'll take it any way I can get it."
The Flames lost leading scorer Johnny Gaudreau to an unsportsmanlike minor for embellishment and a 10-minute misconduct at 8:05 of the third period after he was high-sticked by Blake Comeau, who was given a minor penalty.