Nikita Kucherov had a goal and two assists for the Lightning (43-18-7), who are 4-0-1 in their past five games. Brian Elliott made 27 saves.
"A lot of really bad mental mistakes," Tampa Bay coach Jon Cooper said. "It's too bad. We've got to fight through that. It's a tough League and anybody can beat anybody. You can't make those mental mistakes we made tonight, all throughout the lineup."
The Lightning dropped into a tie for second in the Atlantic Division with the Toronto Maple Leafs.
Tampa Bay will host the Maple Leafs on Monday (7 p.m. ET; NHLN, SN, TVAS, BSSUN, ESPN+, NHL LIVE) for their fourth game in six days.
"Games come at you fast," Cooper said." Everyone gets put through these situations."