Trailing 1-0 in the middle frame, Tavares scored three straight goals for the Islanders in less than 6 minutes, stunning the Sabres with his offensive onslaught.
The hat trick was the second of Tavares' career.
Tyler Ennis and Thomas Vanek contributed a goal and an assist each, and Jochen Hecht also scored for the Sabres.
Buffalo goalie Ryan Miller turned aside 32-of-37 shots.
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