Tim Stutzle
and Brady Tkachuk each had a goal and an assist for the Senators (26-24-3), who have won six of their past seven games, including 4-3 in overtime at home against the Calgary Flames on Monday.
"We know there is room to make up [in the playoff race]," said Tkachuk, who is Ottawa's captain. "But we're not looking at the playoff picture and situation. We're just going in there, playing fast, kind of [doing] our jobs every day and just putting ourselves in the best position to move forward."
Ryan Pulock and Brock Nelson scored for the Islanders (27-23-7), who went 1-for-6 on the power play and lost their third in a row (0-1-2). Ilya Sorokin made 32 saves.
"It's disheartening when you put in an effort and can't break through and put up enough numbers on the scoreboard," New York coach Lane Lambert said. "At the same time, I thought there were some good things done tonight. We just have to move forward and get ready for the next game (against the Pittsburgh Penguins on Friday)."