What is the biggest upset in sports history?

Was it Joe Namath leading the New York Jets over the Baltimore Colts 40 years ago in Super Bowl III (after guaranteeing the win)? The Colts were favored by 18. Or what about the “Miracle on Ice” with the USA men’s hockey team beating the Soviet Union in the 1980 Winter Olympics? Could it be Buster Douglas, a 40-to-1 underdog, shocking Mike Tyson to win the heavyweight boxing crown?

Or could it possibly be the vindication of Al Davis, the most maligned and mercurial sports owner in modern history, for firing 33-year-old Lane Kiffin from the Oakland Raiders (after a 5-15 two-year mark)?