Kyrou said that in the dressing room following the second period, the Blues said, "'Let's not let this, [being] down by however many goals, just affect us and just quit, and let's go out there and let's play.' Yeah, it was just a crazy comeback."
Sam Reinhart and Gustav Forsling each had two assists, and Spencer Knight made 32 saves for the Panthers (10-8-3), who led 3-0 midway through the first period.
"I thought we did a very good job in the first two and in the third we made errors that are not usual for us, and it cost us," Florida defenseman Rakdo Gudas said. "The biggest thing is to learn from it and forget it, remember the mistake and forget about the loss. It is going to happen. We can't always be the team that comes back. Sometimes that is going to bite you."
O'Reilly began the St. Louis comeback when he cut it to 4-2 at 8:16 of the third by banking the puck off the leg of Knight from behind the net.
Kyrou made it 4-3 at 13:43 with a wrist shot from the top of the right face-off circle after taking a feed from Krug.
"I mean, he's a special player," Krug said. "So when you see him with a lot of speed, I was just trying to look up and make their whole group shift a little bit so I can get him in some open ice. Just put it on his tape, and he's a special player and he'll make something out of nothing sometimes."
Tarasenko tied it 4-4 from the left hash marks at 16:11.
Aaron Ekblad gave the Panthers a 1-0 lead at 1:20 with a turnaround wrist shot after he picked up a loose puck in the slot.