Andrei Vasilevskiy stopped 27 shots for Tampa Bay.
Stamkos gave the Lightning a 1-0 lead when he weaved his way through the defense in front and swept the puck in with 13:18 left in the first period.
Killorn made it 2-0 at 4:51 of the second when he grabbed a rebound and put the puck behind Bobrovsky.
Dadonov’s goal with two minutes remaining in the game cut it to 2-1.
The Panthers appeared to score when Brett Connolly deflected a shot from MacKenzie Weegar into the net with 8:51 to go in the third. It was initially ruled a goal but that was overturned when Connolly was called for a high stick.
Lightning: Visit the Boston Bruins on Thursday.
Panthers: Host the New York Islanders on Thursday.
Source: Fox Sports