Kuznetsova should be favored in this match however the public is trying to ride the Petkovic train(because she beat Azarenka last night) which is why books are making Petko the favorite here. I'll gladly take the better hardcourt player in Kuznetsova at plus money.
Don't forget, Petkovic is far from being in good form. She is only 2-4 her last six matches. Beating Azarenka yesterday did not show her true form, perhaps Aza was just not feeling it. I'm not convinced.
Kuznetsova on the other hand is a very solid hardcourt player. She's 25-13 this year on hardcourts and moves on this surface very well. Books are underestimating Kuznetsova's form right now. She's a solid 6-2 her last 8 matches.
Kuznetsova at plus money is the play.......best of luck.