I just posted a comment in the videos thread, to this effect:
I love how she works that cc backhand. It works like this:
She hits each one a little bit wider, eventually opening up the court so much that her opponent is forced to make a gamble: expect another, even wider cc, or shade back toward the middle of the court. Most of the time, the opponent doesn't believe that Petra can possibly swing the BH any wider, so they end up recovering only to the same "dynamic center" that let them reach the previous shot. And then, sure enough, Petra DOES hit another one even wider, and they can't get to it.
Just one of the many beauties of her game.
I'd suggest it might be fun to list as many of Petra's known weapons as we can. I mean things that she does uniquely well, or that only a few other players also have. Signature shots and patterns that she uses. A few others that come to mind:
- The kill shot or overhead down the middle when her opponent has been yanked side to side like a yoyo. Occasionally someone figures this out, like that one point where Sharapova stayed in the middle and lobbed Petra off it for a winner, provoking much shouting from Sasha.
- The running DTL forehand. Might be my favorite Petra shot. So many times her opponents think they have hit something that is at least forcing, if not a winner, and Petra doesn't look like she's particularly close to it, but then she leans out and that long left arm goes swinging...
- The ad court lefty slice serve. When she has it going along with the down-the-T one, it's a nightmare for her opponent. It's interesting that not every lefty has this shot. Nadal's doesn't have the angle that Petra does, but Michael Llodra does (and more power and spin, being a man), and he uses it to devastating effect in doubles.
- The hook forehand to keep the ball to a righty's backhand constantly. I use this myself as a fellow lefty, and I'm pretty sure it annoys the hell out of my right handed opponents.