I wouldn't say any victory on this list constitutes an upset. Certainly the most satisfying win was the one earned by the St. Louis Rams.
Rookie QB Sam Bradford, already looking like a lock for Offensive Rookie of the Year, had the first 300+ yard, 3 TD game of his career, sure to be the first of many. That wasn't the only excitement in the game, as the Rams held off a late rally by the Broncos, thanks to big plays by big players like MLB James Laurinaitis and DE Chris Long, to get their first road win of the season and first place in the division.
And then there was that whole Spygate thing, making you wonder if this loss isn't the one that eventually get Broncos head coach Josh McDaniels fired.
Don't let me influence your vote or anything.