Tage Thompson scored the only goal of the second period as the Montreal Canadiens and Buffalo Sabres are tied 2-2 after 40 minutes of Game 4.
The Canadiens lead the best-of-seven series 2-1.
Bowen Byram went to the box for the Sabres at the 2:23 mark of the second period as the Canadiens got an early power play.
After the kill, the Sabres went to the man advantage thanks to an Alexandre Carrier double minor for high sticking at 5:56.
Thompson converted during the first two minutes of the infraction when his dump-in deflected oddly off the glass, hit Canadiens goaltender Jakub Dobes and went into the net for an unlikely equalizer.
Montreal went back to the power play after Rasmus Dahlin took his second interference penalty of the game at 11:21.
Bowen Byram took at double minor for high sticking at 18:31 to once again send the Canadiens to the power play.
Montreal will be on the man advantage to begin the third period with the score tied 2-2.
The Canadiens erased a one-goal deficit in the first period to lead after the opening 20 minutes.
Mattias Samuelsson struck first, getting the Sabres on the board after going to the net on the rush and beating Dobes.
Alex Newhook then tied proceedings with his fifth goal of the series as he found a little open space in the slot and converted a pass from Jake Evans to even the score.
Cole Caufield gave the home team their first lead of the game in the dying seconds of the opening period when he drove to the net on the power play and fired the puck past Ukko-Pekka Luukkonen to make the score 2-1.
