Mittelstadt scored two goals in Thursday's 5-2 loss to the Canadiens.
Both goals came after the Bruins had already fallen behind 5-0, but Mittelstadt was at least able to spoil Jacob Fowler's shutout bid. It was the first multi-goal performance of the season for the 27-year-old forward, and through 19 games Mittelstadt has delivered seven goals and 12 points with 28 shots on net and a plus-12 rating.