So at long last, we have our first upset of the championships. I warned yesterday that Wozniacki could be in trouble today, and I was right. Today Sam Stosur put in one of her best performances since the French Open to defeat top seeded Caroline Wozniacki in straight sets. As with most of Wozniacki’s losses, the match was actually pretty straightforward. In the first set, both players held firm until 5-4* when Stosur was able to snatch the break and the set. She brought that momentum into the second set, broke early, and barring a slight stutter while serving for the match, she never looked back.

I have to say, these courts are looking pretty good for Stosur. Though they will never allow her to be as mercilessly aggressive as she is on clay, they’re slow enough. As usual, her serve worked extremely well. The kicker out wide was a nightmare for Wozniacki, and though Karolina repeatedly changed her position on the return, she remained unable to take the ball early and was having to hit most of her returns from above shoulder height. In other words, it was a nightmare.

That said, I was actually more impressed with Sam off-the-ground than on serve. Her backahand admittedly remained as pitiful as ever, but on the forehand side Stosur’s approach was very interesting. She was aggressive, as always, but she was playing with a massive amount of margin and only took measured risks when the opportunity presented itself. And that’s how it should be against Wozniacki. So many times over the last few months I’ve heard people saying that the only way to beat Wozniacki is to blast through her. Yes, that is certainly one way of dealing with her, but it also happens to be exactly what she wants her opponents to attempt to do as 90% of the time they will end up commiting 40 errors and being off the court in 50 minutes flat. To beat Wozniacki, it’s about being smart, dictating (but not mindlessly attacking), and seizing opportunities when they come. Sam did all of that today and so props to her for not only coming to court with the correct gameplan, but executing it impressively.

And as for Wozniacki?

It’s interesting to look around and see what people write about Wozniacki. Recently I’ve seen so many people discussing Wozniacki and her gamestyle, and while most seem to agree that she is far to defensive/lacks the weaponry to snatch a slam at this very moment, many believe that she will improve rapidly to the point where she can. I disagree. Why? Her technique.

On both groundstrokes her technique is just not good enough to even ever be called an “aggressive counterpuncher”. On the forehand side, She has huge problems with her hit point, she over-extends her followthrough, and her legs, body and racket move completely out of sync. Her backhand side is certainly by far a better stroke, but many of those properties also arise when she tries to be aggressive and leans into her shots. The thing about technique is that it’s not something that can just be taken apart and put back together. If she tried to, she would probably end up with even worse results than before. So she’s stuck with it.

But she is clearly aware of that, and that’s why she compensates for it by playing high percentage and low risk tennis. There’s absolutely nothing wrong with it. But it means that she’ll never be able to march her way to a slam, or take out a top player when playing at the level that Stosur was at today.

Tomorrow she will be up against Francesca Schiavone. The pair have played twice this year - once en route to Fran’s French Open victory and then at Toronto on hardcourts. Francesca is playing far better than she was in Toronto, however. If she can expose all of those technical shortcomings (as she did in Paris) by mixing up the pace, angle and trajectory of her slice and topspin strokes, she stands a good chance. If not? Expect Wozniacki to stand firm and grind Schiavone down to nothing. She almost always does.