Ehrhoff fired a wrister from the slot over goalie Anton Khudobin, who anticipated a low shot and went down early. Cody Hodgson added an insurance goal less than 3 minutes later when he tipped in a pass from Tyler Myers.
Myers began the comeback 2 minutes into the third period, tying the game at 2 by backhanding in a rebound after Khudobin stoned Jochen Hecht on a 2-on-1 break.
The goals completed a stirring comeback for Buffalo, which trailed 2-1 going into the third. Entering the game, Boston (8-2-2) had outscored its opponents 15-5 this season in the final period.