Anderson, who also played for the Panthers from 2006-09, is 10-1-1 against them in his career. It looked as if his remarkable run might end after the Panthers scored two power play goals midway through the first period.
"I had to hit the reset button there," Anderson said. "We didn't get the start we wanted. Going down 5-on-3, they capitalized on their power play. ... In the second and third the momentum changed in our favor."
Ottawa won for the 13th time in its last 15 games against the Panthers. Florida remains winless in the Atlantic Division (0-6-1) this season.
The Senators broke a 2-all tie with a fortunate bounce on a power play. Corvo took a shot from above the right circle and the puck bounced off Greening's leg and over Thomas' shoulder and into the net with 43 seconds left in the middle period. The goal was upheld after a review by officials.
"It's interesting how goals come," Greening said. "They come in all shapes and forms. Tonight was an odd one but I'll take it."
Ottawa stretched its lead to 4-2 in the third on Ryan's goal.
Jared Cowen's pass got by three Panthers players and found Ryan's stick in front. He pushed the puck past Thomas at 11:52.
The Panthers have given up at least one power play goal in each of their last six games.
Trailing 2-0 halfway through the first, the Senators scored twice in the period to tie it. They closed to 2-1 on Corvo's goal. His wrist shot from the point got past Thomas on the stick side at 10:58.
Condra scored with 1:15 left in the first to tie the game at 2 when he poked in the puck from in front on a pass by Jason Spezza from behind the net.
"I thought Craig was very competitive tonight, but at the same time was very calm in the net," Senators coach Paul MacLean said. "That was good to see. That gave us momentum after we were down 2-0, and then we were tied up before the end of the period. That certainly helped us a lot."
The Panthers made the most of a 5-on-3 power play in the first, scoring two goals. Tomas Fleischmann's shot from the point was blocked, but Huberdeau was near the crease and swept in the rebound to make it 1-0 at 6:44. Fleischmann broke a nine-game pointless streak with the assist.
Later in the power play, Campbell made it 2-0 after his slap shot from the left circle went over Anderson's shoulder and into the net at 8:22.
This was the first time the Panthers scored two power play goals in a game since the home opener, a 6-3 win over Pittsburgh on Oct. 11.
Thomas faced 45 shots, the most the Panthers have allowed this season. The previous high was 40 against Boston on Oct. 17.
"We came out, get the 2-0 lead and it's our job to keep it and not let the momentum switch no matter what happens," Thomas said. "I felt I played well tonight."
The Senators had seven power plays.
"Mistakes and took a lot of penalties, some warranted, some probably not," Campbell said. "That doesn't help when you're killing a lot. ... It's frustrating."
Senators D Marc Methot returned to the lineup after missing one game with the flu. ... Senators D Chris Phillips played in his 1,100th NHL game. ... Panthers D Dmitry Kulikov, a former first-round draft pick in 2009, was a healthy scratch. ... Winnipeg Jets coach Claude Noel was in attendance. The Jets play the Panthers on Thursday.