Here, finally, came a game in which the Islanders went up against a top-end opponent and checked just about every box, including that most important one: winning. This was needed in every way, this comeback 4-2 victory over the Panthers on Sunday night at UBS Arena which saw the Islanders put together a four-goal third period to beat the defending Stanley Cup champions on the night Mike Reilly returned to the lineup following heart surgery. For the emotional state of this club, whose sole win since trading Brock Nelson was a lacking performance at San Jose, for the playoff race in which the Islanders just sort of keep hanging around, and for Reilly — whose recovery after more than four months out is nothing short of remarkable — this was sorely, desperately needed. Reilly’s presence made Sunday about more than hockey, with the defenseman skating nearly 15 minutes, notching an assist and looking as though he had not missed a beat mere months after doctors found an abnormality with his heart while recovering from a concussion. Reilly’s career was never at risk, but that is the sort of thing to make anyone pause and take a beat. To come back and play so soon, and to do so at a high level in an important game, is as much and more as anyone could have asked. Even so, this was trending toward another loss, and another game in which the Islanders’ goal-scoring proved the decisive issue after trading Brock Nelson. Early in the third period, after a third scoreless power play of the night, a “Let’s go Panthers” chant was heard at UBS with the Islanders trailing 2-0 in a moment which threatened to be the wrong kind of emblematic. Shortly thereafter, Marc Gatcomb put the Islanders on a pathway to making sure it would not be. The fourth-liner took his own rebound off Tony DeAngelo’s initial shot and scored a wraparound goal to bring the Islanders within 2-1, giving them some badly needed momentum. The lack of a fourth power play following what looked like a Gustav Forsling trip on Gatcomb ended up being a blessing in disguise for the Islanders, as just seconds later, Maxim Tsyplakov got free on the rush to score his first goal since December, tying the game at two off a feed from Reilly. All of 17 seconds later, the Islanders were in the lead after Noah Dobson made a play straight out of his 2023-24 season, forcing a turnover in the neutral zone and taking the puck all the way before finishing past Vitek Vanecek for a 3-2 lead. That, in the end, would hold against a frantic Panthers push at six-on-five, with Ilya Sorokin keeping the puck out during multiple scrambles at the crease before Simon Holmstrom’s empty-net goal sealed it. Just a couple nights after an everything-but-the-goals performance while losing in overtime to Edmonton, the Islanders picked up right where they had left off against the Oilers: knocking on the door, but struggling to bring it down. The Panthers, meanwhile, needed all of three shots to produce their opening goal, with Aleksander Barkov feeding Sam Reinhart off Forsling’s rebound just a minute into the second period. By the five-minute mark, Barkov had doubled the lead, tipping Reinhart’s shot at the tail end of a Florida power play, with the puck bouncing off Sorokin, then looping over the goaltender’s head like an eephus pitch. It appeared for everybody that the Islanders were marching toward a fourth straight defeat, yet another night where their scoring would be in question, with the conclusion that they just don’t have enough firepower to compete after trading Nelson staring everyone in the face. That very well might be true. But if the Islanders are going to put up a fight against such an idea, this was a good way of starting.