"It was a weird game," Kesler said. "The whole building seemed dead tonight. I think it was a product of what was on the ice. For whatever reason, both teams seemed sluggish in the second period and both teams were playing defensively, so you're not going to get a lot of shots."
Ottawa had not won since Jan. 10, 4-3 against the Toronto Maple Leafs.
"I'll be honest with you," Senators coach Guy Boucher said. "We never talked about the streak. We just talked about the opponent, what we wanted to do and what we wanted to do after the games we played well. The last two games were good games that slipped away in the third, and we wanted to make sure that, in the third period, we had a solid one, and we did."
Karlsson one-timed a pass from Matt Duchene past Ducks goaltender Ryan Miller for his fifth goal of the season.
"I think that today we played as good as we have this year," Karlsson said. "We know we needed to do that to play against a team like this, and even though we played our best hockey today, I think that they did a great job too. They held us accountable when we made mistakes and they made us earn everything that we got out there."
Miller made 30 saves for the Ducks, who were without John Gibson because of a lower-body injury he sustained Tuesday in a 3-1 win against the Boston Bruins.
"He held us in there when they had their chances," Anaheim coach Randy Carlyle said of Miller. "That's what a veteran goaltender is capable of doing. He didn't get rattled, and I thought that the hockey game was up for grabs."
Bobby Ryan gave the Senators a 1-0 lead when he deflected Mike Hoffman's point shot on a power play at 4:37 of the third period.
