Petra Kvitova [2] v Maria Sharapova [4]

Kvitova overcame the giant killer Sara Errani in the quarter final, but not without a struggle. 48th-ranked Errani, who had sent three seeds packing in her past three matches, raced to a 4-1 lead in the second set before Kvitova stormed home for a 6-4 6-4 win. With her thumping groundstrokes, both forehand and backhand, the Czech star has dropped just one set this tournament. She also has a proven Grand Slam record, beating Sharapova for the Wimbledon title last year.

One thing that she cannot afford, though, is for Sharapova to start dictating the play. Kvitova is not the quickest player on the court, and will struggle to impose herself if the powerful Russian starts running her around.

Sharapova reached the semifinal after defeating countrywoman Ekatarina Makarova in straight sets. She slammed 26 winners to 10 in a win that took just 87 minutes. The Russian glamour girl has played a brilliant Open. She hardly broke into a sweat as she dropped just five games in her first three matches. She has enjoyed a charmed run to the semis, having not played anyone ranked higher than 14.

Sharapova broke onto the world scene in 2004 when she won Wimbledon at just 17 years of age, and her game has only gotten stronger. She moves quickly, she hits powerfully, and she serves consistently - above 70% in each of her past four matches. She also grunts loudly. If there's one thing Kvitova can take advantage of it is her temperament. When her head drops, Sharapova is liable to lose a string of games quickly, as she did against Sabine Lisicki on Monday night.

That said, Sharapova is never out of a match, and is one of the best fighters on the tour. Her drive is unequalled, and with revenge for Wimbledon on her mind, I think the Russian will be too good here.

Prediction: Sharapova in three.

Look out for: Kvitova hiding under her towel at the change of ends.

Victoria Azarenka [3] v Kim Clijsters [11]

Azarenka has breezed through to the semis relatively comfortably. She did not meet a seed until the quarters, and even though Agnieszka Radwanska took a set off her in a tie-break, the third seed dropped only two games thereafter. This was a continuation of some scintillating form for the powerful Belarusian, who has conceded fewer than two games per set so far - and that includes the tie-breaker.

There is hardly a weak point in Azarenka's game. Both her forehand and backhand are dominant, but her power is matched by her precision is hitting the lines. Perhaps she could mix things up a bit more in terms of her positioning - she doesn't come to the net very often - and putting a few more first serves in wouldn't hurt, but her all-round game is very impressive.

Clijsters ensured that incumbent top seed Caroline Wozniacki remained without a Grand Slam title, knocking her out in straight sets on Tuesday. The Belgian totally overpowered the Dane in spite of fears surrounding the ankle she injured in the previous match.

The reigning champ has now produced two of the wins of the tournament, against Wozniacki and Na Li, a game in which she famously saved four match points. Only one player, Jennifer Capriati, has ever won a major having saved that many in the same tournament. Could we be witnessing history?

My guess is, probably not. Clijsters is a classy player and one of the most determined to boot, but I don't think she has the power to get on top of Azarenka for long periods of a match. Azarenka is in devastating form and she should grunt her way to the final.

Prediction: Azarenka in two.

Look out for: the cash symbols flashing in the eyes of nearby ear-plug salesmen.