Mamin flipped a shot on the short side that bounced off the back of Devils goaltender Cory Schneider at 8:38 for his second goal of the season.
Aleksander Barkov added his second goal of the game and 23rd this season on a 2-on-1 break at 16:26 nearly eight minutes later.
Taylor Hall and Jesper Bratt scored for the Devils.
Florida's Roberto Luongo posted 29 saves.
Schneider returned to the lineup and recorded 26 saves. He missed 16 games due to a groin/hip injury, last playing in a 3-2 loss against Boston on Jan. 23.
He returned to action this week after making a start at AHL affiliate Binghamton on Tuesday.
The Panthers went 9-3-0 in February, lifting them to within five points of Columbus entering Thursday for the Eastern Conference's final wild-card spot with three games in hand on the Blue Jackets.
In the debut of new Devils forward Patrick Maroon, acquired from Edmonton at the trade deadline and playing on the fourth line's right wing, Florida scored in the first period on a collision in front of Schneider at 6:51.
Barkov slid a shot on goal from a tight angle, and Schneider made the initial stop. But New Jersey rookie center Nico Hischier, battling with Florida's Nick Bjugstad, had the puck deflect in as he skated hard through the crease and into his goalie.
New Jersey challenged for goaltender interference, but the goal call on the ice was confirmed for a 1-0 lead.
Barkov's 22nd goal gave the Finnish center a career-high 60 points.
New Jersey answered with another goal that went off an opposing player.
Hall's shot from the point was inadvertently directed past Luongo by defenseman Aaron Ekblad 50 seconds into the second.
--Field Level Media
New Jersey | Florida | |
Patrick Maroon 2 | Points | Aleksander Barkov 2 |
Jesper Bratt 1 | Goals | Aleksander Barkov 2 |
Patrick Maroon 2 | Assists | Evgenii Dadonov 2 |
Taylor Hall 1 | Power Play Goals | N/A |
N/A | Short Handed Goals | N/A |
Cory Schneider .897 | Save Percentage | Roberto Luongo .935 |
Cory Schneider 26 | Saves | Roberto Luongo 29 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
New Jersey | 31 | 2 | 1-2 | 2-2 | 9 | 26 |
Florida | 29 | 3 | 0-2 | 1-2 | 9 | 36 |