Tampa Bay didn't generate a ton of chances in the first period, but they took full advantage the ones they managed to create, scoring three goals on seven shots to take a 3-1 lead.
His scoring drought now behind him with a goal on Thursday, Anthony Cirelli found the back of the net for the second-straight game, giving Tampa Bay the lead on a breakaway three minutes into Game 4. From along the right boards, Killorn worked the puck free to the middle of the ice for Cirelli who slipped his shot on the break through Sergei Bobrovsky's five-hole.
Yanni Gourde double the Lightning's lead at 7:24 of the first on a deflection. Kucherov's shot from the point appeared to be going wide of Bobrovsky but Gourde's tip brought it back on frame and put Tampa Bay up 2-0.
Jonathan Huberdeau put home a rebound on Florida's lone power play chance of the first, but another deflection goal late in the period put the Bolts back up by two. From the right point, Erik Cernak fired a slap shot toward Bobrovsky that changed direction off a tip by Palat in the slot.
A pair of goals from Killorn 1:34 apart early in the second pushed Tampa Bay's lead to four.
Killorn struck first on a power play at 5:41, getting open in the crease and tapping home a slap pass from Kucherov. He scored again two minutes later, this time snapping home a shot from the slot after Steven Stamkos chased down a loose puck in the corner.
Florida made their third goalie change of the series to date following Killorn's second goal, going back to Chris Driedger after Bobrovsky had allowed five goals in less than 30 minutes.
Tampa Bay was called for four penalties over the final 11:37 period and Florida got one back on their third power play of the period while Mikhail Sergachev was in the box for roughing. From the left circle, Carter Verhaeghe cut to the middle of the ice and lifted a backhander over Andrei Vasilevskiy to make it 5-2 late in the period.
Kucherov put to bed any hope of a second-straight Florida comeback with a power play goal early in the third period. A puck behind the Panthers' net came free for Stamkos and he slipped a cross-ice pass to Kucherov at the opposite circle for a goal that sealed the win.
It was a concerning end to the game for Tampa Bay, however, as Kucherov and Sergachev exited with injuries.
Kucherov exited midway through the third after taking a slash behind the play from Anthony Duclair. He remained down on the ice in visible pain while the trainers came out and struggled to put weight on his left leg on his way back to the locker room.
With 3:36 to play and the outcome no longer in doubt, Patric Hornqvist ran Sergachev into the boards behind the Lightning net. Sergachev's back took most of the collision with the wall and he was face down on the ice for over a minute before gingerly skating off the ice and to the locker room.
Scoring Summary
1st Period
TBL | 3:00 Anthony Cirelli (2) - Alex Killorn, Erik Cernak
TBL | 7:24 Yanni Gourde (2) - Nikita Kucherov, Mikhail Sergachev
FLA | 8:49 Jonathan Huberdeau (2) - Patric Hornqvist, Sam Bennett - PPG
TBL | 16:45 Ondrej Palat (2) - Erik Cernak, Nikita Kucherov
2nd Period
TBL | 5:41 Alex Killorn (2) - Nikita Kucherov, Victor Hedman - PPG
TBL | 7:15 Alex Killorn (3) - Steven Stamkos, Anthony Cirelli
FLA | 18:45 Carter Verhaeghe (2) - Aleksander Barkov, Jonathan Huberdeau - PPG
3rd Period
TBL | 4:47 Nikita Kucherov (3) - Steven Stamkos, Alex Killorn - PPG