Hartman scored the game-winning goal in Sunday's 4-2 win over the Lightning.
With the score knotted at 2-2 midway through the third period, Hartman took a pass from Kirill Kaprizov, spun to his forehand and ripped the puck past Andrei Vasilevskiy from right on the Tampa Bay netminder's doorstep. Hartman has now found the back of the net in five of the last six games, continuing a breakout campaign that has seen the 27-year-old collect 12 goals and 16 points through 21 contests.