Jared McCann, facing the Panthers for the first time since the four-player trade on Feb. 1 that sent him and Nick Bjugstad to Pittsburgh for Derick Brassard and Riley Sheahan and three draft picks, scored a short-handed goal for the Penguins (28-19-7).
"I thought he had a strong game," Sullivan said. "He can really skate. He was real good on the penalty kill. He gets a huge goal for us, short-handed. I thought his line was better 5-on-5 tonight. I think he's getting more comfortable with how we're trying to play. He's getting better with each game, but I thought he had a real strong game tonight."
Marcus Pettersson scored, Kris Letang had two assists and Casey DeSmith made 39 saves in place of injured starter Matt Murray.
Dadonov opened the scoring with a power-play goal at 5:22 with a backhand after Matheson's shot from the point bounced off the end boards to the front of the net.
It was Dadonov's first goal in nine games.
"He's snake-bitten and getting upset and frustrated by it," Panthers coach Bob Boughner said. "I've had lots of talks with him. He's working hard and he finally got paid off tonight, which is nice to see. Our power play has been doing a lot of that, getting point shots and seconds and thirds around the net. Good to see that one go in."
McCann tied the score 1-1 at 13:51 of the second period with a wrist shot on a 2-on-1 after the Penguins caught the Panthers in a line change.