Originally Posted by NadalAgassi
Maybe you missed it but the title was "in form Serena". The answer would probably be someone like Na Li who can match her power, apart from the serve, almost always gives Serena a tough match, and tends to let loose and go for broke when she feels like the big underdog. Maybe Kvitova on a fast court if she gets her sh1t back together. Both of those are even a stretch though, the real answer is probably nobody currently on tour. There are a number of players who can beat Serena out of form (not Sharapova mind you).
I agree with you. Na Li is a good choice if Na is also playing well.