Kyle Okposo had two goals in New York's fourth consecutive victory. The Islanders (18-22-7) also have won seven straight road games.
The Islanders rallied past the Stars after trailing 2-0 after one period for the second time in a week. This time, New York scored three goals in the final 4:16.
Dallas (20-18-7) has lost six in a row for the first time since March 2011.
Dallas goaltender Dan Ellis stopped 27 shots.
SABRES 2, CAPITALS 1, SO
WASHINGTON (AP) — Cody Hodgson decided a lacklustre game with the only goal in the shootout, and Buffalo avoided matching the longest road losing streak in franchise history.
Hodgson, returning after missing eight games with a hand injury, beat Philipp Grubauer in a skills contest that mirrored the rest of the game — not many quality chances, hardly any pucks in the net.
Jason Chimera also scored in the opening period, and Grubauer made 30 saves for the Capitals, who have lost five of seven.