Hate to say it, but Jimmy Johnson, Thanksgiving Day, 1991. Washington was dominant, undefeated (11-0), a championship team that would later blow out every comer in the playoffs. The skins lost in week 17 resting starters. Their only real loss that season was because Jimmy Johnson had a day for the ages. We would probably have two undefeated NFL champions if not for that game, and the 91-92 Redskins would be widely regarded as the best team in league history. Dallas was 6-5 and trying to believe in their coach who kept telling them how good they were. Dallas won the game 24-21. The Redskins were obviously superior, but that day the difference was Jimmy Johnson schooling Joe Gibbs over and over again to keep Dallas in the game. Dallas didn't lose again that regular season finishing with 5 straight wins. They lost to Detroit in the playoffs, badly. But the future was bright and they won 3 of the next 4 Super Bowls. I still believe, that one game where Jimmy Johnson did everything right and took the needed risks (and had some luck for being willing to gamble), was responsible for the mini dynasty in Dallas. Without that win that team continues struggling to believe in the fast talking coach. With it, history was made.