"I think it's just a sense of relief, said Anders Lee, who scored twice for New York. "It's been a tough stretch."
Oliver Wahlstrom, Kieffer Bellows and former Senator Jean-Gabriel Pageau also scored for New York (6-10-5), which had last won on Nov. 6. Ilya Sorokin stopped 30 shots.
"We stuck together and we started to build on our game a little bit the last few nights, but we hadn't been able to get that extra point in overtime," Lee said. "It starts to wear on you quite a bit. So, for us to come out tonight and get the win that we needed, play the right way for good stretches of time, it's exactly what we needed out of our group."
The Senators saw their three-game winning streak come to an end, but know exactly how the Islanders feel as they were piling on losses before this last stretch.
Ottawa was coming off a 3-2 shootout win over New Jersey Monday night, and seemed to run out of steam after a stretch of five games in seven nights.
"We just didn't have the same sharpness with our execution tonight," said head coach D.J. Smith. "I wouldn't say that it was the effort, we just weren't playing as smart. You know, we had some chances and we didn't put it in. We didn't break out as good. You know, at the end of the day, you don't get the result you wanted."
The biggest concern coming out of the game may be the play of Filip Gustavsson, who made 22 saves, and has now lost his last four starts.
There were a couple goals he will want back, and Smith says he'll have to find his way through this tough time.
"Gus is a real good goalie, you know," said Smith. "We've seen him play really well. He's gonna have to bounce back. He's gonna, you know, he's gonna get some starts here before Christmas and he's going to have to, you know, be at his best."
Josh Norris, Nick Holden and Alex Formenton scored for Ottawa, (7-16-1), which now has three days off before hosting the defending Stanley Cup champion Tampa Bay Lightning Saturday afternoon.
The Islanders felt they were due after having lost two games in overtime and one in a shootout.
"It feels good," said Islanders coach Barry Trotz. "I mean, it's incredible to think about what we've gone through in the last month. I've never gone through it. These guys have never gone through it. The way we just stuck together and battled.
"I've got to give them a lot of credit. Finally, they got rewarded. It felt good. It felt good to have a little life in the dressing room after the game. Music blaring and guys ribbing each other."
The Islanders led 3-1 heading into the third and were able to make it 4-1 early on as Bellows roofed a shot over Gustavsson, but Ottawa was able to cut the lead in half two minutes later as Holden scored his first of the season as it deflected off New York's Noah Dobson.
Pageau then scored his third of the season at the 12-minute mark of the third, taking advantage of some confusion in front of the Senators' net.
"I guess we kind of ran out of steam or got away from our game a little bit," said Holden. "Those are the games that we've all got to learn to win so that consistently when you don't have your best effort for a full 60 minutes you still can win games."
Formenton picked up his fifth of the season with a short-handed goal to round out the scoring.
After a scoreless first period, the Islanders jumped out to a 3-1 lead after 40 minutes.
Lee opened the scoring three minutes into the second when he picked up his own rebound and backhanded it into the net.
Ottawa tied the game on a power play goal by Norris, who one-timed it past Sorokin.
Wahlstrom restored the Islanders' lead when was able to walk in on Gustavsson and beat him shortside at 14:06 of the period. Just 27 seconds later, Lee scored his second of the night as he picked up a puck that took a weird bounce off the back boards and beat Gustavsson from in close.
Both teams had a number of solid chances in the opening period. Sorokin made a huge save on Tim Stutzle late in the period that left the 19-year-old shaking his head.
Notes: Senators defencemen Victor Mete and Michael Del Zotto and forward Adam Gaudette were healthy scratches. The Islanders Matt Martin was a scratch as he is dealing with a lingering injury. Casey Cizikas remains the Islanders last player in the NHL's COVID-19 protocol.