What a person should wear is entirely his/her personal choice.Religion should be a person's personal matter and should not be imposed on anybody.
Yes Rafael Nadal does wear shorts below his knees,but he's always has been comfortable in them.Majority of the Men wear shorts that reach above the knees.
As regards to Sania,in women's tennis there's not a single player who wears a "below knee" attire.That's the norm in Ladies tennis and Sania was following the norm.
When Sania plays she represents India ,not Islam.That's the reason why so many of us support her.
Every body knows that the Fatwa was wrong.But some educated muslims knowing fully well it was wrong,try to justify the issue because they find opposing it an unislamic thing to do.
All I can say is that it's high time educated muslims take a hard look at themselves and see if they are doing enough to improve their community.They should also realise why such issues happen only with muslims