Kennedy's redirection of a Shawn Matthias shot broke a 2-2 tie and proved decisive as the Panthers rebounded from a pair of shutout losses in their previous two games.
Jose Theodore turned aside 8-of-10 shots over the first two periods before leaving with game, reportedly with cramps. Jacob Markstrom came in to weather a third-period onslaught in which he saved all 18 Islanders shots he faced.
Mark Streit and John Tavares found the net for the Islanders.
New York's Evgeni Nabokov stopped 29-of-32 shots.
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