while this is true, isn't it also true that the US had to win both games in order to win gold... I know it wasn't necessarily a gold medal game, but going into the soviet game we knew we had to win the next two to take gold. Otherwise I think the soviets still could have won if the US lost to Finland.
Or maybe my math is off...
Wikipedia does a great job of explaining the format. After spending some time playing out various scenarios, it turns out USA actually did not need to win both, but things would have been very tricky otherwise, it's interesting to see what else could have happened though. There were two groups of six teams, and the top two in each group advanced to the final round. Turns out their second game of the tournament, a 7-3 win over Czechoslovakia was of utmost importance because a loss there would have resulted in USA finishing third in the pool and Czechoslovakia advancing to the final round while USA would have played Canada in a game to determine fifth place for some reason.
The game against the other team in your group that advanced with you to the final round carries over. USA tied Sweden and USSR beat Finland, so before the final round started, the standings looked like this:
The Miracle on Ice game was the first game of four in the final round, and if USA would have lost, they would have had no chance at a gold medal. If the Soviets would have tied it up, USA would no longer have control over their own destiny. They would have had to beat Finland and also hope for Finland to beat Sweden and Sweden to pull off a big upset over the Soviets. Finland tied Sweden later that day, so if USA and USSR tied, the standings would have been spaced out the same with each team having one game left.
This would have meant that going into the last day, USA against Finland was a must win but for the final game of the tournament, Sweden-USSR, things would have been pretty tough. A USSR win would have meant silver for USA. Another unlikely Soviet tie would have meant a standings tie at the top between USA and USSR which could have resulted in a gold for USA if they would have beaten Finland by three (or maybe two depending on what the next tiebreaker was). A very unlikely Sweden win over USSR would have resulted in a tie between the Swedes and Americans, and since their goal differentials would have been the same going into that last day (again, this is all a hypothetical situation in which USA and Russia tied) the gold medal would have been decided by who won their game on that last day by a larger margin--USA over Finland or Sweden over Russia.
So at the end of the day, USA vs. USSR wasn't 100% a must-win, but it was a must-not-lose. However, even with a tie there, gold would have been very unlikely because they would have needed USSR to falter again with either a loss or a tie against Sweden, and even then USA would have needed a wide enough goal differential. By holding off the Russians for those last ten minutes after Eruzione's goal, it put USA in first place in the pool and all they needed to worry about was beating Finland. As long as they took care of business against Finland, none of the other teams could have caught up to them in the standings, it didn't matter what the goal differentials were or what happened in any of the other games.
NOW, since this is my first free day in over two months and I'm up relatively early, let's see what would have happened with a different result against Finland. Going into the final day, the standings looked like this:
Finland 1 3
A loss to Finland would have really complicated things. Finland would have pulled into a tie with USA and would have had the tiebreaker. Going into that last game between Sweden and USSR, things would have been very interesting. With Sweden and USSR both only one point behind, the winner of that final game would have won gold (ended up being USSR by the score of 9-2) and the loser would finish in fourth and go home with nothing while Finland would leave with silver and USA the bronze. However, if that Sweden and USSR game would have ended in a tie, it would have resulted in all four teams finishing with three points. Now I'm not sure if wins was a tiebreaker or if it went straight to goal differential after points, but if it was wins then Sweden would have been gone because they would have ties against all three other teams and no wins. If it's goal differential, theirs was zero and USSR's would have been -1. Going into the USA/Finland game, USA's was +1 and Finland's was -2.
If USA would have lost to Finland by anything more than one goal and Sweden and the Soviets tied, USA would not have won gold. If it was a one goal game, USA would have still had the higher goal differential than Finland and USSR, but would have been tied with Sweden. I'm not sure what would have happened then, because head-to-head wouldn't solve anything since USA tied Sweden head-to-head.
If USA and Finland tied, a winner in the USSR-Sweden game would have tied with USA for first place. If Sweden wins by one or Russia by two, then their goal differential ties USA and I'm not sure what happens next. If Sweden wins by more than one or Russia by more than two, then that team wins gold.
If anyone knows more about what the tiebreakers were back then or if I am incorrect about anything, please let me know!