Erik Haula had a goal and an assist, and Akira Schmid made 25 saves for the Devils (21-8-2), who are 0-4-1 during their skid.
"Again, we get behind right off the start," New Jersey coach Lindy Ruff said. "Take a penalty, they score a power-play goal. You look at a couple of the goals, they're not goals we want to give up. … What was the strength of our team was really how well we play defensively. When you start to get a little frustrated offensively, you start to cheat.
"The backbone of our game has been how well we play defensively. We can't get away from that."
Reinhart put the Panthers ahead 1-0 at 8:54 of the first period when his backhand pass intended for Matthew Tkachuk deflected in off the leg of Devils defenseman Jonas Siegenthaler during a power play.
"I liked our first period an awful lot," Florida coach Paul Maurice said. "I thought we had a good template of how we wanted to play the game. Then we got into a little trouble. After that, it was just will. Grind, block shots, spit it out, spit it in and get to the net."