Ondrej Palat, Victor Eklund and Simon Holmstrom scored, and Matthew Schaefer had his eighth assist in nine games for the Islanders (5-3-1), who extended their point streak to four games (3-0-1). Ilya Sorokin made 15 saves.
Frank Vatrano and Alex Killorn scored for the Ducks (4-5-1), who have dropped four straight and were coming off a 5-2 loss at the New York Rangers on Monday. Lukas Dostal made 22 saves.
Palat gave New York a 1-0 lead at 13:39. After Sorokin got his glove on a Cutter Gauthier wrist shot from the top of the slot, Anthony Duclair fed Jean-Gabriel Pageau off the rush for the Islanders. Pageau then found Palat cutting to the slot alone before Palat beat Dostal high glove side from the inside edge of the left face-off circle.
Eklund extended the lead to 2-0 at 16:28 when he backhanded the rebound of his own tip attempt with Dostal out of his net.
Vatrano cut the deficit to 2-1 at 17:18. A.J. Greer found him all alone at the top of the crease, and Vatrano deked to his backhand before beating Sorokin over the glove.
Holmstrom made it 3-1 on the power play at 18:44, deflecting a Schaefer point shot.
Islanders forward Brayden Schenn hit the right post on the power play at 19:00 of the second period.
With Dostal on the bench for the extra attacker, Killorn one-timed a Leo Carlsson pass at the left hash marks at 17:20 for the 3-2 final.
