Slow court tennis is quite unpredictable.
Li looked like a sure winner until her ankle did her in.
A lot of Nadal projections looked similar (he is 23, look at his slam count, blah blah).
Statistical regression may be a "natural" human tool. But life has other plans. Perhaps no plans is more accurate.
"Can you pass the car ahead of you by following it's tracks?" - LeeD, Talk Tennis Guru.