The Lightning took a 4-3 lead at 14:40 of the third when Steve Downie passed the puck to Ritola, who poked in a shot from the crease. Seconds later, the Lightning stretched their lead when the puck caromed in off of Purcell.
Tampa Bay had tied it 3-all on Pyatt's goal at 9:01 of the third.
The Panthers scored 41 seconds apart in the second. Versteeg swept the puck in from the left circle at 4:59 to give the Panthers a 2-1 lead. Kopecky then put a shot past Garon.
The Lightning cut it to 3-2 when Connolly scored during a 5-on-3 advantage.