Bellows, in the lineup for the first time since Feb. 18 after forward Anders Lee sustained a lower-body injury Thursday, tied it 2-2 on a snap shot from the left face-off circle at 1:59, then gave New York the lead when he powered his way to the net from the right wing and stuffed a shot past Mackenzie Blackwood at 5:10 to make it 3-2.
"It's obviously been a while, but I just wanted to go out there and work hard and grind down low ... just be responsible," Bellows said. "It was a good team effort to get the win, so that's the most important thing."
Semyon Varlamov made 26 saves for the Islanders (18-6-4), who have the longest active winning streak in the NHL and extended their point streak to 11 games (10-0-1).
"I thought we could have easily lost the game; I didn't like our battle for the first two periods," New York coach Barry Trotz said. "I thought Varlamov was by far our best player. Our forwards didn't have enough bite in their game and I thought our defense corps bailed them out, [along] with our goaltending."
Blackwood made 26 saves for the Devils (8-13-3), who lost a New Jersey-record 10th straight home game in regulation. It has not won here since a 2-0 victory against the Islanders on Jan. 24.
The teams play here again Sunday.
"We had some opportunities to maybe execute a little better in some situations and that kind of got us in trouble a little bit in the third," Devils forward Travis Zajac said. "But they're also a structured team. They thrive in these tight games, so we have to just do a better job with the lead. We've got a chance to come back tomorrow and put in a good effort."