from Kerry Fraser of TSN,

Some will say that the contact exerted by Smith was minimal and insufficient to knock the net off the moorings without some responsibility placed on Atkinson. The replay shows that Atkinson's momentum and forward progress was altered significantly and he accelerated from his initial stop inside the top of the crease after the contact by Smith was initiated and completed. It is also evident that Atkinson attempted to push back and stop following the contact by Smith with a second, separate spray of snow from his skate blade.

Referee Chris Rooney made an excellent, quick decision when he correctly applied rule 63.6 to award the goal to Atkinson following the actions of Smith that "accidentally" caused the goal post to be displaced prior to the puck crossing the goal line.

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If you want to watch/review the goal, see below...