Volkov scored on a shot from the right face-off circle to make it 4-2 at 11:42, but Aleksander Barkov answered at 12:36 to push the lead to 5-2.
"We were playing slow and turning pucks over," Lightning forward Pat Maroon said. "We were just too slow in the [defensive] zone, especially against that team. We shot ourselves in the foot. That's not how we're supposed to be playing."
Volkov scored from in close to cut it to 5-3 at 15:50, and Tyler Johnson finished an odd-man rush at 16:38 to make it 5-4, the seventh goal of the period.
"We had a good start to the period, got some goals, and you saw they got desperate and upped their game, and we couldn't handle their surge," Panthers defenseman Anton Stralman said. "It turned out to be wild, and then it kind of settled down in the third."
The Panthers tightened up on defense, and Driedger made consecutive saves on Stamkos and Mikhail Sergachev after Aaron Ekblad was called for hooking at 18:14 of the second.
"Go back to the late kill in the second and they had all the momentum," Quenneville said. "We stabilized it a little with that kill. We got our composure back."
Stralman extended Florida's lead to 6-4 with his first goal of the season 59 seconds into the third period.
"[That goal] was huge," Driedger said. "Seeing [Stralman] do a little dipsy dangle and go shelf is pretty cool too."
The Lightning had another power play with 3:15 remaining in the third period and pulled McElhinney for a 6-on-4 advantage.
"I thought the game was winnable the whole time," Cooper said. "We scored four. I felt great going into the third period, and to give up a goal in the first minute is inexcusable."
NOTES:It wasHuberdeau's 153rd NHL goal, moving him past Pavel Bure into fourth place in Panthers history behind Scott Mellanby (157), Barkov (160) and Olli Jokinen (188). … Barkov's two points gave him 421 to move past Jokinen for second in Panthers history. Huberdeau is first with 454. … Carter Verhaeghe had two assists for Florida. ... Johnson has three goals in his past two games.