John Beecher scored just over two minutes into the game to give the Boston Bruins a 1-0 lead over the Toronto Maple Leafs after the first period of their first-round series opener on Saturday.
Jesper Boqvist and Pat Maroon recorded assists on the play which marked Beecher's first playoff goal.
William Nylander was not in the lineup for the Leafs due to an undisclosed injury.
Toronto outshot Boston 12-10 in the opening frame.
Boston won all four matchups with the Leafs during the regular season.