Fun win, but pretty much inconsequential. They needed to win in regulation to have a shot at the #1 seed in the group. The US will still face one of the Czechs or Russians* in the first round of the elimination tournament, most likely. Really fun comeback, but the US needs to be better if they want to defend gold. Nobody on the backend can even begin to fill the hole that McAvoy left.
*The Russians have medalled in each of the past 7 tournaments, and only failed to medal 4 total times since the fall of the Soviet Union. You really don't want to draw them in the first round