Even if she goes 1-2 she can still be the YE#1. What needs to happen though is she needs to win the title, which means advance with a 1-2 record and Serena cannot make the finals at all
Masha still have a chance right? If Petra loses against Wozniacki then Maria can still hope because she won a set at least
Yes but if I'm not miscalculating Petra has to lose in two sets against Caroline while Maria has to win in two against Aga (which, given that both Maria and Caro play well and Petra and Aga play an average match, is not even that unlikely)
this is a lesson to MYSELF; never doubt the Princess after some disappointing results. (US Open, Cincinnatti, New Haven, basically the whole hard season )
Same scoreline, and under an hour again. 
and 
at the same time.. Lawd.
)