Anderson extended it to 2-0 at 8:36. Swayman made the save on Evans’ deflection of Mike Matheson’s shot from the right point, but Anderson came off the left post to bat the rebound out of the air and past Swayman stick side.
“Against a team like Montreal, it’s unacceptable to start like that,” Boston captain David Pastrnak said. “It’s on us players to take the responsibility. I thought we got the guys ready and we were ready, and overall, we weren’t.
“Even though it was much better the second half of the first period and the beginning of the (second) we got going, we got our legs going, but forgot about defense and gave up too many breakaways. And against a skilled team like Montreal, they’re going to punish you.”
The Canadiens have yet to trail at the end of the first period this season.
“We were just very flat,” Bruins coach Marco Sturm said. “There was nothing going on. I thought David’s line was the only line early on. They pushed, they worked, but overall, it was just very, very flat, and all of a sudden we were down 2-0 because of it. So that was the disappointing thing for me today. Just not good enough. I think we can all be better.”
Evans made it 3-0 on the breakaway at 4:24 of the second period. Anderson’s stretch pass sent Evans in alone to score on a backhand between Swayman’s pads.
Caufield pushed it to 4-0 at 8:14. He drove in alone and fired a wrist shot past Swayman’s glove for Montreal’s second straight breakaway goal.
Phillip Danault extended it to 5-0 at 14:15 with a one-timer between DiPietro’s pads from the top of the right face-off circle.