Nicholas Robertson and Matthew Knies each had a goal and an assist for the Maple Leafs (43-22-9), who have won three in a row and five of seven. Ilya Samsonov made 26 saves.
Toronto pulled to within four points of Florida for second place in the Atlantic Division.
“I think [the game] was a lot more physical and fast-paced. It looked like a playoff game, for sure,” Knies said.
Vladimir Tarasenko had a goal and two assists for the Panthers (47-23-5), who are 2-6-1 in their past nine games. Sergei Bobrovsky allowed five goals on 16 shots before being pulled after two periods. Anthony Stolarz made six saves in relief.
Florida remained two points behind the Boston Bruins for first place in the Atlantic.
“(We found) more urgency (in the third period),” Panthers defenseman Brandon Montour said. “We found some ways to obviously bring some energy, and obviously it’s tough when you go down like that. Guys fought to the end, but it is what it is.
“All their goals were in the crease or close to our net. Easy mistakes, uncharacteristic of our team, but it is what it is. Tough tonight.”
Robertson gave the Maple Leafs a 1-0 lead at 13:59 of the first period. He took a pass from Knies in the neutral zone and scored on a breakaway past Bobrovsky’s outstretched right pad.
“I was going deke (all the way), he plays really low,” Robertson said. “He’s a very good goalie, really quick, so fortunately it went in.
“[The intensity] was high. We definitely wanted to send a message and start on the right foot against Florida. We’ve got them one more time, but if it’s Florida (as Toronto’s opponent in the first round of the Stanley Cup Playoffs), it’s Florida. If not, we just want to start playing really good hockey towards the playoffs.”