After Sean Kuraly's goal stood following video review, putting the Bruins up by three with 9.2 seconds left, David Pastrnak scored for Boston 41 seconds into the second period on the resulting power play. It gave Boston a four-goal lead during a 7-2 victory at Enterprise Center.
The Bruins lead the best-of-7 series with Game 4 here Monday (8 p.m. ET; NBC, CBC, SN, TVAS).
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By rule, St. Louis was assessed a delay of game penalty after the challenge because the call was not overturned. When the sequence was over, Boston led 4-0, and a once-raucous crowd had gone quiet.
Blues coach Craig Berube said he felt he had no other choice but to request the coach's challenge to try to stop the Bruins' momentum going into the second period.
"I thought it was 50/50," Berube said of the chances of having the call overturned. "I think if we go in there (trailing) 2-0 (going) into the second, it's a big difference than 3-0."
The Blues contended that Bruins forward Joakim Nordstrom was offside, but the Situation Room confirmed that St. Louis defenseman Joel Edmundson passed the puck into the defensive zone prior to the goal. Rule 83.1 states, in part, "If a player legally carries or passes the puck back into his own defending zone while a player of the opposing team is in such defending zone, the offside shall be ignored and play permitted to continue."