Islanders 2, Senators 1
Casey Cizikas scored with 6:27 remaining in the third period to snap a tie as visiting New York completed a sweep of the home-and-home series.
Brock Nelson also tallied for the red-hot Islanders, who have won 13 of their last 15 contests. Jaroslav Halak made 20 saves en route to his franchise-record 11th consecutive victory.
Mika Zibanejad netted the lone goal for the Senators, who honored Daniel Alfredsson prior to the game after the long-time former captain announced his retirement earlier in the day. Craig Anderson turned aside 23 shots as Ottawa suffered its fourth straight loss and sixth in seven games.
New York's Thomas Hickey, who scored the winning goal in a 3-2 overtime victory over Ottawa at home on Tuesday, factored in the decisive tally again. The defenseman made a cross-ice pass from along the left-wing boards to Cizikas, who beat Anderson from the inner edge of the right faceoff circle to give the Islanders a 2-1 edge.
Both teams used their power play to score in the second period. Nelson poked a loose puck in the crease past Anderson at 11:45 after Frans Nielsen's pass attempt from behind the net hit Ottawa defenseman Cody Ceci's skate, and Zibanejad drilled a one-timer from the top of the left circle between Halak's pads during a 5-on-3 advantage with 4:53 left in the session.
GAME NOTEBOOK: Alfredsson was honored during a pregame ceremony after spending all but one of his 18 seasons in the NHL with Ottawa. Alfredsson's wife and four children took part in the ceremonial first puck drop, with the 41-year-old Swede and current Senators captain Erik Karlsson facing off. ... New York RW Michael Grabner made his season debut after missing the first 25 games with a lower-body injury and registered two shots in 13:11 of ice time. ... Halak has allowed a total of 14 goals during his winning streak. ... Ottawa RW Bobby Ryan returned to the lineup after missing two games with a fractured finger and unleashed three shots in 17:34.