A couple years ago the same thing happened to my beloved Nebraska Cornhuskers.
They had a few losses, but they were still looking at a possible Big XII-North title, and they still hadn't lost a home game in years. Texas rolls into town ranked #2 and #3 in the country. Nebraska misses three field goals in the game, but somehow despite that, we're only down by 3 points at the very end of the game.
We're on the 12 yard line with 30 seconds to go.
On first down, our option quarterback who can't throw decides to throw into triple coverage.
Ball game. We lost at home, and then got spanked for the next couple of games. Nebraska's streaks of ending up ranked in the AP at season's end, non-losing seasons (we finished at 7-7), 9 win seasons, etc. all ended. We also had the nation's longest home winning streak at the point.
It hurt.