Napoleon Bonaparte was once asked what qualities he looked for in a general. He certainly wanted intelligence, courage and a fighting spirit, but none of those were the most important attribute in his mind.
Instead, the trait Bonaparte said was most important was whether or not the man was lucky. He figured luck was something that followed great men wherever they went and was a significant part of why they achieved the levels of success they did.
In the football world, the idea of good fortune is usually thought to have an entirely different meaning. Most of the time it is associated with average teams that post good records (e.g., a team with 6-6 talent that goes 8-4). It isn't often applied to elite or near-elite programs because the sports world in general figures that a dominant record cannot come about as a product of providence.
The truth of the matter is that Napoleon was right. Luck can be just as much of a factor among top-level talents as it can among mid-level ones.
This is what has happened to some extent with the Arizona Wildcats' defense.