The two Original Six rivals played a tight back-and-forth game through 60 minutes and headed to overtime with the score tied 2-2. Mid-way through the extra frame, Blackhawks forward Philipp Kurashev got past Canadiens defenceman Jeff Petry at the blue line and skated in on a breakaway. Before Kurashev could get a shot off Canadiens forward Mike Hoffman hit him, sending both forwards flying into Canadiens goalie Samuel Montembeault and knocking the net off its pegs.
After two long video reviews, officials determined that Kurashev had scored the game-winning goal on the play and the Blackhawks celebrated their third-straight victory. The Canadiens, who have now lost five straight, were naturally disappointed, with head coach Dominique Ducharme calling the whole situation "tough to swallow."
But why was this goal allowed to count? Let's look closer at both reviews to figure that out:
Review 1: Did the puck go in the net?
The first thing the officials looked at was whether the puck actually crossed the goal line. In this case, the video clearly showed the puck continued to slide across the line between the goalposts -- or at least, where the posts should be. While the net was off the pegs at the time the puck slid across the line, the goal was allowed to count thanks to Rule 63.7, which states:
"In the event that the goal post is displaced, either deliberately or accidentally, by a defending player, prior to the puck crossing the goal line between the normal position of the goalposts, the Referee may award a goal. In order to award a goal in this situation, the goal post must have been displaced by the actions of a defending player, the attacking player must have an imminent scoring opportunity prior to the goal post being displaced, and it must be determined that the puck would have entered the net between the normal position of the goalposts."
In a statement released after the game, the NHL said that the video review determined that Hoffman (the defending player) "caused the net to be displaced from its moorings prior to the puck crossing the goal line." As a result, the goal was awarded to Kurashev because he was not at fault for the situation that caused the net to be knocked off as the puck slid into it.
Review 2: Was Kurashev off-side?
The second review was to determine whether Kurashev was off-side when he entered the offensive zone. This review was initiated by the situation room and was not a coach's challenge due to Rule 38.3, which states that the situation room assumes responsibility to check any scenario that normally falls under a coach's challenge in the final minute of the third period and overtime.
On this play, Kurashev received a cross-ice pass from Brandon Hagel near the Canadiens blue line. Kurashev reached behind himself to collect the pass and slid the puck forward before skating into the zone for his scoring chance.
According to Rule 83.1, the position of a players' skates will determine whether he entered the zone before the puck and was therefore off-side: "A player is off-side when both skates are completely over the leading edge of the blue line involved in the play."
The second component of this review involves control of the puck. To keep the flow of the game going, the NHL has a rule to help prevent players from accidentally putting themselves off-sides while carrying the puck. That rule, also under 83.1, states "A player actually controlling the puck who shall cross the line ahead of the puck shall not be considered 'off-side,' provided he had possession and control of the puck prior to his skates crossing the leading edge of the blue line."
On this review, officials determined that Kurashev's skates were still in contact with the blue line when he received the pass from Hagel, and that he had control of the puck before both of his skates completely crossed the line. For those reasons, he was on-sides and allowed to proceed into the zone and eventually score the game-winning goal.