With 20 minutes in the books, Florida led 31-14 in shot attempts and 16-9 in scoring chances.
In the second period, the Panthers looked like they were about to head to a 5-on-4 power play after Scott Perunovich interfered with Ryan Lomberg in the neutral zone. But Lomberg was also called for embellishment on the play even though he popped right back up.
On the ensuing 4-on-4, Ryan O'Reilly swiped a puck in the offensive zone and teed up Jake Walman for a heavy slap shot that flew past Sergei Bobrovsky to put the Blues up 2-1 at 6:36.
Cleaning the slate and pulling the Panthers even going into the intermission, Sam Reinhart, who had already scored in each of the two previous games, found the back of the net yet again when he buried a rebound after a shot from Carlsson to make it 2-2 with two minutes left in the period.
"They're a tough team to play against," Reinhart said of St. Louis, which fell to 12-8-4 with the loss. "They don't give up much. Structurally, they're very sound and they play a tight game. I liked our determination. We were able to stick with it. We kept battling through it."
Early in the third period, the Blues regained the lead when Brandon Saad took a cross-ice pass from O'Reilly and sent a shot past Bobrovsky from the left side of the net to make it 3-2 at 4:29.
But after pulling Bobrovsky in favor of the extra attacker with a draw coming up in the offensive zone late in the period, the Cats found the game-tying goal when Anton Lundell won the faceoff back to Mamin for a quick top-shelf snipe to make it 3-3 with just 2:34 remaining in regulation.
"I just heard a sound off the post, and it was in," Mamin smiled when asked about the play.
Following a scoreless overtime in which the Panthers came oh-so-close to scoring on several attempts during a 4-on-3 power play, Lundell and Reinhart each beat Ville Husso in the skills competition before Bobrovsky shut the door on O'Reilly to secure two points with a 4-3 victory.
Pelted with pucks all game, Husso finished with 48 saves for the Blues.
At the other end of the ice, Bobrovsky stopped 22 shots to improve his record to 11-1-2.
"Everybody has stepped up," Brunette said. "That's what good teams do."
Here are five takeaways from Saturday's win in Sunrise…