Ryder was awarded the shot after Thrashers defenseman Johnny Oduya hauled him down from behind following a turnover in the Atlanta zone. Ryder unleashed a snap shot past Ondrej Pavelec with 7:29 remaining to give Boston the lead.
The Thrashers, meanwhile, saw their last hopes for a post-season berth snuffed out with the setback.
Dustin Byfuglien and Evander Kane scored and Pavelec stopped 20 shots for Atlanta.
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