Well if this thread is about (at all) best moments when it comes to a competitive aspect then Kage beating Mango twice is one of the better ones.
Maybe it isn't a favorite for some people because of different reasons, all have different taste, but when it comes to big "WTF" moments in this games history this clearly is one of the better ones. The defending champion losing is always huge but losing TWICE at the same tournament is even more then so.
I might be biased because I can't for my life understand why people think Ganon is "that good" so for me personaly it feels even bigger because I think Ganon is worse then most people. But either way it's really big, no question asked.
Good job, Kage! =)