Sam Bennett made it 4-3 at 15:13 when he jumped out of the penalty box to create a 2-on-1 rush and finished it with a snap shot that beat Vasilevskiy on the stick side.
"It's not a good feeling being in the box twice there, especially after they scored one," Bennett said. "I was a little anxious in the box there, but I was able to come out and 'Lundy' made a great play to find me, and I was able to put it in. Definitely a little weight off my shoulders."
Luostarinen extended the lead to 5-3 at 13:02 in the third period, chipping in a puck from the low slot off a centering pass from Marchand. Reinhart added an empty-net goal at 15:36 for the 6-3 final.
"He's been great ever since he came to the Panthers and he's a great guy to have around," Barkov said of Luostarinen. "You see how much skill he has that maybe doesn't always show up on the scoresheet. He kills penalties with his high hockey IQ, he's really good on the forecheck ... and today he got rewarded with four points. He has been very important for us since he got here, and he keeps getting better."
NOTES: Luostarinen's four points set a Panthers record for a road playoff game, and he became the first player in club history with four points in a potential series-clinching game. … Tampa Bay has lost nine of its past 10 playoff games at Amalie Arena. ... Verhaeghe scored in consecutive games. ... Lightning forward Nikita Kucherov has not scored in 15 straight playoff games. ...Panthers forward Matthew Tkachuk had an assist and finished with five points (three goals, two assists) for the series. ... The Lightning were 2-for-18 on the power play in the series.