The WTA has a nice breakdown right here.  My predicted winners are in BOLD.

[4] Agnieszka Radwanska (POL #4) vs. [13] Ana Ivanovic (SRB #13) – I think Radwanska wins in straight sets, but Ivanovic has had a nice event.

[2] Maria Sharapova (RUS #2) vs. Kirsten Flipkens (BEL #43) – Sharapova is on a roll and I don’t see that ending here.

[5] Angelique Kerber (GER #5) vs. [19] Ekaterina Makarova (RUS #19) – I’ll take Makarova in a mild upset.