Streit opened the scoring with 2:09 remaining by capitalizing on an odd-man rush. Moulson set up the goal by driving up the right side and patiently waiting for the play to develop. Streit got a step on Sabres forward Kevin Porter and snapped in Moulson's pass through the middle into the open right side.
Grabner then scored on a breakaway after he intercepted defenseman Christian Ehrhoff's lazy pass across the middle inside the Islanders blue line.
"Not a good play. I've got to know I'm out against Grabner and he likes to cheat on those plays," Ehrhoff said. "It's frustrating. You have to put it behind you."
Nothing got behind Nabokov.
He got his pad out to stop Steve Ott's one-timer from the slot with 7:25 left and, a few seconds later, somehow got his glove up to deny Tyler Ennis' backhander from in close.
About two minutes later, Nabokov made a glove save to rob Drew Stafford, who was alone to the right of the net. Nabokov then somehow managed to snag a backhander that Vanek directed at the net through a screen.
Add it all up, and the 2-0 deficit marked the 18th time in 19 games this season the Sabres haven't had a lead entering the third period.
Improving to 6-3-1 on the road this season, the Islanders will now turn their attention to addressing their struggles at home.
New York, an NHL-worst 2-6 at home, will open a seven-game homestand on Sunday against Carolina.
"We have no choice, but we have to play better in front of our fans," Nabokov said.
NOTES: The Sabres have lost 12 times through their first 19 games for the first time since a 4-12-3 start in the 1986-87 season. ... Sabres D Alexander Sulzer missed the final two periods because of a lower body injury. ... The Islanders recalled G Kevin Poulin from AHL Bridgeport after veteran G Rick DiPietro cleared waivers and was assigned to the minor league club. ... Sabres rookie C Mikhail Grigorenko returned after sitting out three games as a healthy scratch.