Jordan Eberle and Mathew Barzal scored in the shootout and the Islanders beat the Senators 5-4 giving coach Barry Trotz his 800th win.
Brock Nelson, Anders Lee, Devon Toews and Ross Johnston scored in regulation to help the Islanders recover after giving up a two-goal lead in the third period and snap a two-game skid.
Robin Lehner stopped 21 shots before leaving with an injury late in the third period.
Thomas Greiss came on, stopped both shots he faced through overtime and denied Thomas Chabot and Bobby Ryan in the shootout.
The Islanders pulled into a tie with Washington atop the Metropolitan Division with identical 38-21-7 records and 34 regulation/overtime wins.
Trotz became the fourth coach in NHL history to reach the 800-win mark, joining Scotty Bowman (1,244), Joel Quenneville (890) and Ken Hitchcock (842).