Rask came up big in the final period as the Bruins were clinging to a one-goal lead, especially with 2 minutes remaining when he made a glove save on a point-blank shot by Marian Gaborik.
Loui Erikkson's first goal as a Bruin, 49 seconds into the third period, broke a 1-1 deadlock and Milan Lucic added an empty-netter to seal the win for Boston, which improved to 3-1-0 to start the season.
Chris Kelly also scored for the Bruins.
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