Charlie McAvoy had a goal and an assist for the Bruins (20-16-1), who have lost four of their past five games (1-3-1). Joonas Korpisalo allowed five goals on 17 shots before being replaced in the second period by Jeremy Swayman, who made 10 saves in relief.
“We knew they were going to come hard and we weren’t ready for it,” Korpisalo said. “Trailing 3-1 after the first is not ideal. ... We just need to get back to our identity, battle hard, play together and bring back the energy. We didn’t have it today.”
Batherson gave the Senators at 1-0 lead at 1:30 of the first period. He received a quick touch pass from Nick Jensen in the high slot and beat Korpisalo over his glove.
“We were playing good coming in, and with the way the standings are this was a huge game, a four-point game,” Batherson said. “We came out ready to go and it paid off for us. ... We did a good job keeping the lead throughout the game. It’s a big win against a team like that.”
Giroux made it 2-0 at 13:44. During a scramble in front, Batherson kicked the loose puck over to Giroux, who scored past Korpisalo's right pad at the left post.
“It was disappointing right from the start,” Boston coach Marco Sturm said. “They came out flying, they came out skating. They came out with more energy and outworked us.”
Zetterlund pushed the lead to 3-0 at 16:47 with a power-play goal. He took a pass in the bottom of the left circle and roofed a shot into the small window over Korpisalo’s right shoulder.
“We complement each other great,” Zetterlund said of his linemates, Tim Stutzle and Brady Tkachuk. “We’re skating, we want the puck, we want to hold onto it, create some space out there, and when we bring it to the net things happen.”
David Pastrnak cut it to 3-1 during a 5-on-3 power play at 19:07 of the first, scoring with a one-timer from the right circle that snuck past Ullmark.
Stutzle made it 4-1 at 6:44 of the second period. He won a battle with Pavel Zacha for a loose puck to the left of the crease and lifted a shot over Korpisalo from his knees.
Cozens extended the lead to 5-1 just 19 seconds later. He scored with a slap shot from the right point that made its way through traffic and ended Korpisalo's night at 7:03.
“It was a big goal. It was a big goal for the whole group," Stutzle said. "They’re a good team over there. They have some really good players, and we knew they were going to come out hard. We did a really good job of fighting back and killed their momentum.”
