Mattias Samuelsson gave Buffalo a 3-2 lead just 52 seconds later at 16:36. He received a pass from Jack Quinn and beat a screened Swayman high to the blocker side with a wrist shot from the top of the left circle.
“I saw ‘Quinner’ coming out of the corner with the puck. Not sure where the winger was, but I thought it was pretty open there. I just tried to call for it,” Samuelsson said. “Quinner made an unbelievable play, and I thought I could slip it short side there.”
Tuch added an empty-net goal at 18:48 to push it to 4-2.
Pastrnak scored a power-play goal to make it 4-3 with eight seconds remaining, but the Bruins weren't able to win the ensuing face-off and get one final attempt on net.
“I thought we were in the perfect spot. We were exactly where we wanted to play, being in that position with five or six minutes left in the game,” Boston coach Marco Sturm said. “You could tell they got a little bit frustrated and, yeah, we made pretty much two mistakes to let them tie up the game.
“Obviously, with the crowd behind them, they got some life and the game is done. Very unfortunate because my guys played really well. Really well. But that’s playoffs. That’s something we have to learn again the hard way. We just have to stick with it for 60 minutes.”
Geekie gave Boston a 1-0 lead at 10:52 of the first period. Rasmus Dahlin blocked Pastrnak’s initial shot, but Geekie skated into the puck at the right hash marks, where he beat Luukkonen glove side with a slap shot.