Despite taking an early lead, the Flames fell 5-2 to the Blues Wednesday night in St. Louis.
Mikael Backlund scored twice for the Flames. Eddie Lack, in his first start for the club, stopped 24 of 28 shots in the loss.
"I felt kinda little rusty to start the game," Lack said. "To be honest, I felt like I was battling a little bit with the traffic and my puck handling and everything. Felt like after a bit, I calmed down.
"I mean, obviously it's never fun letting four goals in, but I thought I made a couple of good saves down the stretch there, but wasn't enough."
Alexander Steen, Jaden Schwartz, Alex Pietrangelo, Paul Stastny and Joel Edmundson scored for the Blues while goaltender Jake Allen stopped 23 of 25 shots.
The Flames had an energetic start to the game and it paid off in the form of Backlund's first goal on the night.
Video: CGY@STL: Backlund nets Tkachuk's delicate dish
Backlund jumped onto the ice while the Blues were moving the puck around the Flames' zone and he immediately used his stick to disrupt the play. He then carried the puck up the ice to the Blues' end and eventually capitalized with a quick shot past Allen to give the Flames the first goal of the game.
"I think tonight was one of the best games I've seen Backs play," linemate Matthew Tkachuk said. "And last game in Nashville, it was one of the best games I've seen Fro (Michael Frolik, the third member of the line) play, if not his best one. I think this road trip was maybe good to get our mojo back a little bit."
After Backlund's ice-breaker evened things up for the Blues when he wristed the puck far-side past Lack.
A couple of penalties cost the Flames in the second period as Schwartz and Pietrangelo scored back-to-back powerplay goals to allow St. Louis to claim the lead. With Sam Bennett sitting in the box for tripping, Vladimir Tarasenko's shot ringed off the post and back to him. He spotted a wide-open Schwartz, who made it an easy tap-in to make it 2-1 for the Blues.
Then, with Frolik off on a hooking call, Pietrangelo snapped the puck past Lack for the multi-goal lead.
"So, two nights in a row we've given up two-for-three, two-for-three on the powerplay," coach Glen Gulutzan said. "When you're playing your back-to-backs, your penalty kill has to be better. Our penalty kill, quite frankly, doesn't look anything near what it should, and we've got to clean that area up. Because tonight it put us in a hole. Nashville, it put us in a hole. Tonight, we couldn't get out of it.
"The biggest issue with the penalty kill right now is our zone entries. We are not stopping people. They're walking into our zone uncontested, setting up. And if you're going to let somebody stay in your zone for two minutes, you can't get a clear, but if you can't even stop them from coming in, you're going to get scored on. That's just the nature of the game. I like our in-zone kill; being organized at the blueline right now and denying entires is not where it needs to be. It's not NHL level, and we've got to get it there."
Video: CGY@STL: Backlund tallies second on Allen's blunder
Backlund drew the Flames back within one when Allen fell behind his own net while trying to play the puck. Tkachuk got to it first and dished it to Backlund, who raced to get in position to score on the wide-open net for his second of the game.
While the Flames fought back, just as they had the night before in Nashville, they were unable to tie the game.
"I thought there were two saves in particular that he kept us in the game and gives you a chance," Gulutzan said of Lack's performance late in the game. "And that's what you need in a back-to-back. That's what you want from your second guy, and he gave that to us tonight. We just let him down on the specialty teams."
Late in the third period, Stastny beat Lack high and far side to re-establish the multi-goal lead. Edmundson's empty-netter iced the game for the Blues.
ONE-TIMERS: This was the 10th multi-goal game of Backlund's career. He needs two more goals to reach 100 … Today is the one-year anniversary since the 3M Line - consisting of Matthew Tkachuk, Mikael Backlund , and Michael Frolik - was assembled. Their first game together was on Oct. 25, 2016, a 4-1 win in St. Louis … Troy Brouwer played the 697th game of his career … Tkachuk grew up in St. Louis, where his father, Keith, played for nine seasons.
NEXT UP: The Flames return home to the Scotiabank Saddledome, where they'll host the Dallas Stars on Friday at 7 p.m. MT. After that, the Washington Capitals will come to town for a Sunday night game at 7 p.m. MT.