Fisher scored off a rebound at 2:38 of overtime to give Ottawa its fourth consecutive victory, 3-2 over the Tampa Bay Lightning on Wednesday night.
"We've felt like we've upped our game and we're finding little ways to win and trying to be patient regardless of the circumstance in the game," Fisher said. "I think we've done a good job of not panicking and tonight we stuck it out and got a big win."
Chris Phillips took a shot from 30 feet out that goalie Karri Ramo stopped, but Fisher controlled the rebound in the slot and scored his 11th goal of the season.
"I was just trying to crash the net and Philly got a good shot on net and I was able to get the rebound," Fisher said. "It was nice to get that one in overtime. I don't think we played our best game and we have to be better in certain areas."
Brian Elliott made 22 saves for his fourth victory in a row, and Ryan Shannon and Chris Kelly scored in regulation. The Senators were 5-2-1 on the homestand.
Tampa Bay's Cory Murphy and Adam Hall scored, and Ramo stopped 24 shots.
The Lightning, coming off a 9-3 home loss to Carolina on Saturday night, have lost four in a row and 15 of 19.
"We played hard," Lightning coach Rick Tocchet said. "I don't think we gave them much and the goals that they did get they were opportunistic. I thought we played good and I was happy after our last game that they came out with this effort.
"You can tell the guys played a lot harder than Saturday, but it was still a tough one because you want to win these types of games."
Ottawa's Jason Spezza appeared to score with just under 5 minutes to play, but the goal was immediately waved off because Spezza kicked the puck into the net. After a video review, the call on the ice stood.