Sergei Gonchar netted the deciding goal late in regulation, helping Ottawa get past the New York Islanders, 5-3, at Nassau Coliseum.
Jakob Silfverberg, Zack Smith and Guillaume Latendresse also scored in the final 20 minutes for the Senators, who have won three in a row and four of six thanks to scoring four times in the third period.
Matt Kassian tallied for Ottawa in the first, while Ben Bishop made 26 saves.
"We definitely didn't have our best first two periods, but we've got great leadership in here," Ben Bishop said. "There's not one guy in here who is going to quit."
Josh Bailey, Keith Aucoin and Lubomir Visnovsky provided the offense for the Islanders, who lost for the third time in their last eight.
Evgeni Nabokov stopped just 18 shots in defeat.
The Senators assumed a one-goal edge with one minute remaining, as Gonchar's right-point shot caromed off a body in front and sailed past Nabokov for a 4-3 game.
"The game-winning goal they got should have been a whistle," Islanders head coach Jack Capuano said. "It was a high stick and Ottawa touched it first."
Capuano was referring to the stick of Ottawa's Mika Zibanejad, which appeared to bat the puck out of the air well above his shoulder and into the Islanders zone, setting up the goal.
Latendresse added an insurance marker into the empty net with 10 seconds on the clock. With an assist on the clincher, Senators captain Daniel Alfredsson collected his 1,100th point.
"I didn't know until I got into the room. It feels good -- coming in a win like this makes it nicer," Alfredsson said.
Ottawa first struck with 6:23 gone in the opening period, as Kassian chopped a Gonchar shot out of the air and through Nabokov's pads from the right side.
Aucoin equalized for the hosts with just over two minutes before intermission, then Bailey put the Isles on top at the 14-second mark of the middle period.
Visnovsky's tap-in of a Matt Moulson pass at the right post on a power play made it 3-1 for New York with 8:14 on the clock.
The Senators scored twice in a 68-second span in the third period to draw even, as Silfverberg lit the lamp on a deflection at 1:07 followed by a turnaround shot from Smith at 2:15.
A potential go-ahead score by Aucoin following a subsequent advantage with almost 7 1/2 minutes played was waved off, ruled to have been kicked in.
Ottawa won two of three in the season series, with the teams splitting a pair on Long Island ... Gonchar added two assists and Patrick Wiercioch notched three helpers for the victors ... Kyle Okposo assisted on a pair of New York scores ... Prior to the game, the Senators announced that forward Milan Michalek had right knee surgery and will be out indefinitely ... Senators defenseman Marc Methot left the game in the second period with a lower-body injury and did not return.