Stamkos and Garon key Tampa Bay's win
Martin St. Louis, Tom Pyatt and Ryan Malone also scored for the Lightning, who were coming off a 2-1 overtime victory at Florida on Friday night.
Garon stopped four shots by former Lightning left wing Sean Bergenheim during the opening period. The goalie turned aside 23 shots in Friday's victory over the Panthers.
Tampa Bay took control during the second when goals by Pyatt, Stamkos and Malone made it 4-0. Stamkos got his second of the game and 14th of the season in the final minute of play.
The Southeast Division-leading Panthers, who went 0 for 6 on the power play, got a late third-period goal from Shawn Matthias.