But center Evgeni Malkin was injured and missed the last 15 minutes of the game.
Malkin was injured with 15:09 left in the third period. Pittsburgh's second leading scorer was driving to the net down the left side and was off-balance after releasing the puck when Erik Gudbranson checked him.
Malkin slid back-first into the end boards, his head snapped backward and he remained down on the ice for several moments, but skated off on his own. There was no penalty on the play.
Pittsburgh coach Dan Bylsma said Malkin was being evaluated and they'd know more on Saturday.
Teammate James Neal called it a "tough hit."
"It's a dangerous spot," Neal said. "I hope he's OK. It (stinks), obviously, seeing (Malkin) go down, but any time any player goes down you just need to adjust and grind out a win, and we did that."
Gudbranson said he just finished his check.
"He was in a vulnerable position but you can't pass up a hit like that," the Florida defenseman said. "It's unfortunate that he got hurt, but it's one I'll take every time."
Two minutes after Malkin left the game, Niskanen took a pass from Kris Letang and scored on a one-timer from the left side.
It was the Penguins' first lead of the game. Jeffrey then scored his first goal since Feb. 18, 2012, when he redirected a shot from Matt Cooke at 15:15 to give the Penguins a two-goal lead.
"It's nice to see different guys chip in," said Pittsburgh captain Sidney Crosby, who had his points streak end at four games. "(Jeffrey), he's kind of been in and out of the lineup so for him to come in and step up and score a goal for us, it's always nice to see those guys rewarded. I thought it was a great effort as a team, as a group."
Florida defenseman Mike Weaver scored the Panthers' only goal. Florida was outshot 40-23 and goaltender Jacob Markstrom made 37 saves after being recalled from the AHL's San Antonio Rampage on Wednesday morning.
It was his first NHL game of the season and just the ninth of his career.
Pittsburgh is tied with New Jersey and Montreal for the most points in the Eastern Conference with 24.
The Panthers beat the Philadelphia Flyers on Thursday for their first win in five games. Pittsburgh got off to a strong start on Friday.
The Penguins outshot Florida 12-3 in the first period and had two power plays to the Panthers' one, but the game was still scoreless.
The three shots by the Panthers were the fewest the Penguins have allowed in a period this season.
Weaver scored his first goal since Jan. 25, 2011, from the point to give the Panthers a 1-0 lead at 8:25 of the second period.
Fifty-eight seconds later, the Penguins got their third power play of the game and Kunitz stood in front of the net and whacked at the puck until he pushed it from under the glove of Markstrom to tie the game at 1-1 at 10:41 of the second.
"I'm not sure we win if we don't get a goal like that," Bylsma said. "We might not get a goal in this game if it's not for him going to the cage and getting that kind of goal."
Right wing Beau Bennett, who made his NHL debut on Feb. 15, started on the Penguins second line with center Evgeni Malkin and left wing James Neal. ... The Penguins have scored at least one power-play goal in 10 straight games. ... Penguins winger Tyler Kennedy was benched for much of the second period after two giveaways. ... Florida's Jonathan Huberdeau ranks first among NHL rookies in goals (13). ... Markstrom was 16-15-2 with three shutouts, a 2.65 goals-against average and a .920 save percentage with the San Antonio Rampage before his recall on Wednesday.