OTTAWA -- All set to get his third point of the night, Erik Karlsson settled for an excellent vantage point to observe the Ottawa Senators' overtime winner.
Karlsson, who had a goal and an assist, was set to redirect Butler's pass from the left side beyond Scott Clemmensen but Campbell's skate got to the puck first.
"He probably saw it too and tried to turn and break off the pass and we got a bit of a lucky bounce, and it doesn't really matter," Karlsson said. "It was nice to stand there up close and see it go in."
Daniel Alfredsson scored his 399th goal on a power play and had two assists for Ottawa, which gave up leads of 1-0, 2-1, and 3-2. Chris Neil scored the Senators' first of two goals with the man advantage and set up Alfredsson for the second. Craig Anderson made 32 saves.
Tomas Kopecky drew Florida even at 3 when he scored the tying goal with 1:12 left in the third and goalie Scott Clemmensen pulled for an extra attacker. Kris Versteeg passed from behind the net to Kopecky, who beat Anderson from the goalmouth as the Panthers' erased their third one-goal deficit.
Michal Repik and Shawn Matthias also scored for Florida, which lost its second straight.
Alfredsson assisted on Chris Neil's power-play goal in the first. Neil got his second point when he set up Alfredsson's goal with the man advantage 7:38 into the third that put Ottawa ahead 2-1.
Matthias drew Florida even at 2 with the game's fourth straight power-play goal at 9:05.
Karlsson restored Ottawa's lead 38 seconds later when his blast from the right point got past Clemmensen for his fourth goal at 9:43.
Alfredsson, who extended his points streak to four games, got his second assist of the game on the play. The Senators' captain has nine points, including three goals and six assists, over the course of his streak.
"I think healthwise I feel like I'm skating and getting up and down the ice at the rate I'd like to," Alfredsson said.
Clemmensen, who stopped 22 shots, turned over the puck to Neil behind his net with the teams tied at 1 in the third. The Panthers' goalie scrambled back in front too late to stop Alfredsson from putting home his 10th goal to move within one of becoming Ottawa's first 400-goal scorer.
Ottawa's Nick Foligno was given a major for charging and a game misconduct 3:01 into the second for his hit on Panthers defenseman Keaton Ellerby behind Florida's net.
Repik, who was recalled from San Antonio of the AHL on Wednesday, got credit for his first goal in six games on the ensuing power play. Versteeg's point shot struck Tomas Fleishmann in front of Anderson before deflecting into the net off Repik's skate.
A video review upheld the goal.
No penalty was originally called on Foligno's hit on Ellerby until referees Tim Peel and Justin St. Pierre conferred and ejected Foligno, who appeared to leave his feet only once he made contact.
"I was extremely disappointed," Foligno said. " I couldn't believe it, actually, so it was more disbelief. I thought it was a clean hit and there's really nothing more to it.
"After two people collide things are going to happen. I definitely didn't leave my feet to hit him. I already knew we were going to hit so there was no point in me leaving my feet. It looked that way but it definitely wasn't."
Ellerby skated off the ice and went directly to the dressing room. He returned shortly after the 5-minute penalty expired.
Panthers coach Kevin Dineen said that though he didn't feel Foligno had any "violent intent" in delivering the hit, he felt the right call was made.
"I think he was trying to make a hockey play and he left his feet and that's against the rules, so I think it was a good rule on the ice and I think that will be the end of it," Dineen said.
Florida center Stephen Weiss left the game in the first with an upper-body injury. He did not return.
"He's not going to play [Friday] night so he'll be out through the holidays and we'll evaluate him [Friday]," Dineen said. "But he's sorely missed. He plays a lot of valuable minutes for us. I'd be very surprised to see him early after the Christmas break."
Neil opened the scoring with his fourth goal 6:58 in when he he deflected Karlsson's point shot past Clemmensen.
Senators right wing Erik Condra stopped the puck from rolling across the goal line with his stick 18:28 into the second after it got behind Anderson.
Weiss leads the Panthers with 21 assists. He is second in points with 32. ... Butler served Foligno's major penalty.