I agree with nomak. Once you get to a certian point, those duels between top echelon can go either way. Its like anything else competetive. The closer you get to the top, the more minor the factor between winning and losing is. Simply a good or bad night could be the difference.
To me, they are some of the best fights though. I know Ive had some enjoyable matchups with (in no particular order)nomde, stang, morph, levi, shane, kappa and the like.