Brett Pesce scored for the Devils (20-16-1), who have lost two straight games. Markstrom made 23 saves.
“We've got to put together three periods,” Devils coach Sheldon Keefe said. “Our second period again here tonight was not good enough. It hasn't been good since Vegas (a 2-1 shootout win on Dec. 17). Vegas was one of our best. The last few have been against teams that are really mobile and fast, with skilled defense. We've had some trouble with that. Lost battles. It's been hard to get it back.”
Pesce gave the Devils a 1-0 lead at 15:35 of the first period. Nico Hischier found Pesce all alone in the high slot before he beat Rittich high glove side.
Rittich denied Jack Hughes’ breakaway at 8:20 of the second with the blocker to keep the Islanders down just 1-0.
“It has been a stretch now where we haven't really been able to put those pucks in the net, and it was a little similar tonight,” Devils forward Jesper Bratt said. “I think we've been working on it as a process. I think we've been talking about it. We have the intention to do better. It's just not really falling into place.”
The Islanders tied it 1-1 at 12:10 of the second period when Markstrom came out of the crease to play the puck and turned it over to Holmstrom, who scored into an open net.
“Things are trending in the right direction,” Islanders captain Anders Lee said. "It was an important divisional game. Our division is so tight that it doesn't separate us from much. So these are big games, really big. And to get one, especially before Bo [Horvat] comes back, to just add one more to the column [was huge].”
NOTES: The Devils are 0-2-0 since Jack Hughes returned from an 18-game absence. ... The Islanders recorded their 10th comeback win this season. The only other teams with a double-digit total are the Flyers (13), Ducks (11), Bruins (11) and Stars (10). ... Pelech scored the go-ahead goal with 1:15 remaining in regulation, the second latest by a defenseman in franchise history behind Ryan Pulock (59:19 on Feb. 11, 2020).