The Senators punched their return ticket to the post-season with the help of Milan Michalek, who contributed a goal and two assists.
Ottawa will make a reappearance in the playoffs following a 13th-place finish last season.
Mark Streit scored and Al Montoya yielded five goals on 32 shots for the Islanders.
Senate Democrats to pull all-nighter on climate change
Teacher apologizes for showing sexual image of herself in class