Point tied it 2-2 at 15:37 when he scored off a pass from Ondrej Palat on a 3-on-2 rush.
Couturier put the Flyers ahead 3-2 with 12 seconds remaining in the second when he scored off the rebound of a Giroux shot.
"Every night, it's a tough challenge, it's a new challenge," said Couturier, whose NHL career-high 18 goals lead Philadelphia. "We had two tough losses against [the] Buffalo [Sabres] and Florida, but we came back with two great efforts against [the] Columbus [Blue Jackets] and Tampa Bay on back-to-back nights. It shows the character of our team."
Defenseman Brandon Manning, who returned after missing 10 games with an upper-body injury, made it 4-2 at 1:53 of the third period when he scored on a wraparound after receiving a pass from Giroux, who has 12 assists during a seven-game point streak.
Johnson made it 4-3 with a shorthanded goal at 8:58, but Valtteri Filppula scored into an empty net at 19:28 to make it 5-3.
"[The Lightning] have been on fire all season playing really well," said Filppula, who played for Tampa Bay from 2013-17. "It's good for us to see where we stand and to know that we have a chance against anybody."