Kris Letang scored, and Casey DeSmith made 38 saves for Pittsburgh (31-22-9), which had its four-game winning streak end.
"We have to realize the situation we're in and every game matters," Penguins defenseman Jeff Petry said. "I thought for a handful of games we played more sound, more structured, so I think tonight was a step back, and we've got to learn from it and be ready for Tuesday (against the Columbus Blue Jackets)."
Sam Bennett, who returned after missing six games with a lower-body injury, gave Florida a 1-0 lead at 19:38 of the first period.
"Obviously, it's tough to be out and watch your team, you want to be out there helping them," Bennett said. "So definitely it was a great feeling being out there tonight, and getting a win always feels great."