Legwand's score off an assist from Francis Bouillon capped a Nashville comeback that saw the Predators erase a 3-1 third-period deficit.
Partic Hornqvist got the comeback rolling 2:57 into the frame when he tucked in the rebound of a Shea Webber shot.
Pekka Rinne improved to 2-0 since signing a seven-year, $49 million contract Thursday, turning aside 35-of-38 shots to earn the win.
Antti Niemi stopped 31 shots in the setback.
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