The Boston Bruins took a commanding 3-0 lead in their best-of-seven series with Philadelphia by defeating the Flyers at the Boston Garden last night, 2-1.

The Bruins dominated the opening minutes of play, allowing the Flyers only one shot on goal. But at the eight-minute mark of the contest, Bob Daily staked the Philadelphians to a 1-0 lead on a power play tally.

In the second period, Bruins rookie John Wensink deadlocked the contest with the first playoff goal of his career by glancing a Peter McNab backhander past Flyer goaltender Wayne Stephenson.

The Bruins set a furious pace for the remainder of the second frame. Both Stephenson and Boston's Gerry Cheevers were forced to make numerous outstanding saves, leaving the score knotted at 1-1 for the opening of the final stanza.

Both teams opened the period sluggishly and seven minutes had elapsed when the Bruins capitalized on their first real scoring opportunity. Terry O'Reilly wriggled down the left boards and centered the puck to a streaking Mike Milbury who chipped it over Stephenson into the net.

The Flyers tried to put on one of their patented third period surges to pull out the game. With one minute to play Stephenson vacated the goal and Philadelphia began to pressure Cheevers, but the Bruins got off a breakaway and time ran out before the Flyers could get off the final shot.