Semifinals are set at the Australian Open and the first one on schedule is Victoria Azarenka vs. Kim Clijsters. Our favorite stats analyst, Omair, was so grateful to provide us with his previews of both the semifinal encounters. Let's  start with the Azarenka vs. Clijsters one.

Azarenka comes into this match knowing that she is one of the two players who have beaten Clijsters twice since she came out of retirement, the other player being Vera Zvonareva, if I am not wrong. Azarenka comes into this match knowing that she won her last match against Clijsters, in straight sets. She comes into this match knowing that the top spot is up for grabs and she will have a huge chance if she stops Clijsters – after all there will be no better way to justify her top spot (if she attains it) than by beating Clijsters in the semis, and then either Maria Sharapova or Petra Kvitova in the finals.

Clijsters comes into this match knowing that this is the last Australian Open of her career, and she intends to go out in style which she showed in her match against Li Na and then against Caroline Wozniacki. Read more »

Petra Kvitova defeated Sara Errani 6-4 6-4 in the Australian Open quarterfinals, but before previewing her semi against Maria Sharapova, our stats pro Omair is giving us a closer look at the numbers behind her victory in the final eight. As an introduction, you can check out our yesterday's quarterfinal preview.

Kvitova took the Rod Laver Arena today knowing that she must get to the semifinals in order to have a shot at the top spot, since her rival Victoria Azarenka had already moved to the semifinals. I guess, that was what motivated Kvitova to come out of the 4-1 deficit and defeat Errani in straight sets.

Errani entered the Rod Laver Arena today knowing well that if she gets past Kvitova today, she will not only end Kvitova's dream of attaining the top spot and winning another major but will also become the first Italian ever to reach the Australian Open semifinals.

Errani fought well, but by the end Kvitova's fire was more than Errani could handle. Her brave play, aided by Kvitova's errors, saw her move ahead to 4-1 in the second set, but only for Kvitova to regroup and win five straight games from there on to put an end to Errani's dream of being the first ever Italian to reach Aussie Open semis. Read more »

Our stats expert Omair was again busy and prepared post-match analytics of the Australian Open quarterfinals whose previews he presented yesterday. Let's first see how the numbers look for the quarterfinal in which Maria Sharapova defeated fellow Russian Ekaterina Makarova 6-2 6-3.

Maria Sharapova took the Rod Laver Arena today with a purpose on her mind, she wanted to prove her doubters wrong, she wanted to show that she too can be a title threat without any match play before the Grand Slam event. She had every reason to be confident when she took the Rod Laver Arena, for she has never lost in the quarterfinals here at Melbourne.

Coming into today's match Sharapova was four out of four in her previous quarterfinals here at Melbourne and she kept that record intact by making it five out of five through to the semifinals.

When Makarova took the court today she had every reason to feel confident. She had beaten Vera Zvonareva in the third round and then topped it off by beating five-time Aussie Open champion Serena Williams in the fourth round. However, that did not help her much against Sharapova, and that did not intimidate Sharapova, who easily breezed past Makarova to book a semifinal clash with Kvitova.

Let us see what the numbers tell us:

Makarova could not keep the level up and going against Sharapova her first serve winning percentage fell. Still, more alarming was her winning percentage on the second serve that fell dramatically to 36%. If that was not enough she could not win points on Sharapova's serve as well, which is considered to be a liability in Sharapova's game. Her winning percentage on receiving points was only 36%. You can never win against Sharapova by winning only 36% of your second serves and 36% of the receiving points. Read more »

Most of you guys have been watching the Australian Open over the last couple of days and hopefully you are excited to get on the tennis court yourselves. In order to help you with your own game, our loyal reader and contributor Florian from OnlineTennisInstruction.com has put together a series of free tennis video tips and decided to promote them on Women's Tennis Blog. Check out his sample video tip below and feel free to tell him your thoughts in the comments and of course if you like the tip sign up to his newsletter to receive more free video tips.

The video tips are meant to be actionable and effective in a short period of time.

Florian says:

Tennis video instruction is helping tennis players all over the world now get a better idea of what they need to do in order to improve and I am excited to be a part of it!

Here is one of his free video tips:

In the Top5 video series, all four areas of the game are covered. There are tips for:

• Improving your groundstrokes and missing less on the net;
• Developing a better service motion;
• Playing smarter and hitting to the right targets;
• Developing more efficient footwork;
• Improving your mental game.

I spent the past 10 years of my life coaching and researching how tennis players can improve and what I found is that most players get stuck at a certain level and often remain there for the rest of their tennis career. Usually they lack the right information to take their game to the next level and my goal with OnlineTennisInstruction.com is to close that gap. – says Florian.

OnlineTennisInstruction.com is a website focused on helping tennis players improve their game. Florian also writes about current events in pro tennis on his blog and recently had a guest post here where he provided us with his Australian Open preview. Visit his website to get more tennis tips.

Our stats lover Omair didn't leave the quarterfinal previews uncompleted, and here he is with his analysis of the quarterfinal between Maria Sharapova and Ekatarina Makarova, following the preview of the Petra Kvitova vs. Sara Errani quarterfinal, and the post-match analysis of the final eight clashes between Kim Clijsters vs. Caroline Wozniacki, and Victoria Azarenka vs. Agnieszka Radwanska.

One thing I am convinced on is that numbers don't lie, after the analyses I did for the first two quarterfinals. When Agnieszka Radwanska entered the match against Victoria Azarenka she was the cleaner player and she just had to play that way to beat Azarenka, but Azarenka was on fire, forcing Radwanska out of her comfort zone. Only if Radwanska had been able to reproduce those numbers in the quarterfinal she would have won, but she failed to do so. As for Wozniacki and Clijsters, the same thing happened to Wozniacki. The last Australian Open quarterfinal on the schedule pits two "ovas" against each other. One is Ekatarina Makarova and the other is Maria Sharapova.

Sharapova did not play any tune-up events in order to give her ankle, that she injured last year in her match against Kvitova, time to rest. Not even a single person considered Sharapova a title threat owing to her lack of play since her injury, and when the draw came out her chances of making it past the quarters looked even grimmer with a potential clash with Serena Williams in the quarterfinals, but here she is in the quarters and not against Williams but Williams' conqueror.

Makarova and Sharapova both have lost one set so far in the tournament. Sharapova enters the match as the favorite, and has beaten Makarova in both their encounters. However, Makarova's run here so far has shown that she can beat anyone on a given day, even in consecutive matches. Read more »

We already have one Australian Open semifinal set – Victoria Azarenka vs. Kim Clijsters – and our stats lover Omair has looked back on their quarterfinal matches. Let's now see what the numbers and Omair are telling us for the upcoming quarterfinal between Petra Kvitova and Sara Errani.

Who would have thought after Kvitova's run to the quarterfinals of the Aussie Open last year that she would be here again next year fighting for her second Grand Slam and the top spot in women's tennis. At least I was not the one, though I was impressed by her game and I rooted for her when she took the court.

Kvitova has shown us so far that she can have bad patches during her matches, but what has been more important is that she can overcome them and storm back to win. After all that is what she did in her second round match against Carla Suarez Navarro, when she was down a break in the third set and she came back to win the match. Almost similar thing happended to her against Ana Ivanovic in her fourth rounder, when she failed to serve out the match in the second set but regrouped to win it in the tiebreak. Read more »

Yesterday our loyal contributor Omair did a statistical analysis of the Australian Open quarterfinal between Kim Clijsters and Caroline Wozniacki, and the numbers spoke in Wozniacki's favor. Despite that, gut feeling told Omair that the Dane was more likely to lose and that's what happened. Now, let's see Omair's post-match review of the 6-3 7-6(4) match.

Going into today's match Wozniacki had a lot on the line, she had a lot of questions to answer, a lot of critics who she wanted to silence by winning this match. Wozniacki's No.1 ranking was on the line, her status as No.1 WTA player was under question, her ability to win a major was what she was seeking answer to when she took the Rod Laver Arena to face Kim Clijsters for a spot in the semifinals. She wanted a revenge, for it was Clijsters who had denied Wozniacki her first major in the 2009 US Open final, it was Clijsters who denied Wozniacki her first year-end Championships when she beat the Dane in the final in 2010, it was Clijsters who dethroned Wozniacki from the top spot for a week in 2011.

Wozniacki had a lot of reasons to be confident when she entered the Rod Laver Arena. There were questions surrounding Clijsters' ankle, which she twisted badly in her previous match, her performance so far at the Aussie Open was cleaner as compared to Clijsters' as per the stats, she had not lost a set while entering into the match, as against Clijsters who lost a set in her previous match to Li Na. Clijsters had never beaten a reigning No.1 at a Grand Slam in her previous five encounters at Grand Slams with the then reigning No.1s. But it all could not help Wozniacki and it all could not stop Clijsters from crushing the world No.1 to book a semifinal spot.

Going into today's match Clijsters was on a mission, since she had already announced that this would be the last Australian Open of her career. She wanted to end it in style, and yes she did it in style to book herself a semifinal spot against the on-fire Victoria Azarenka. She got her first win over a reigning No.1 in a Grand Slam, and did that in authoratative way by defeating Wozniacki in straight sets. What did Clijsters do to emerge as the winner, when the numbers were in Wozniacki's favour? Let us compare the stats of their quarterfinal encounter with the stats of their previous four matches that earned them the quarterfinal spot.

Wozniacki entered the match as the cleaner player, but Clijsters came out of the match as a winner and a cleaner player. Here is a comparison of Wozniacki's stats of the first four matches and her quarterfinal encounter:

Wozniacki's first serve percentage dropped dramatically as compared to her first four matches, as did her winning percentage on those first serves. She entered the match with a positive differential of winners and unforced errors, but she left the match with a whopping negative 13 differential. I think the table speaks in itself as to why Wozniacki lost. Read more »

In Omair's statistical preview of the Australian Open quarterfinal between Victoria Azarenka and Agnieszka Radwanska the numbers were more on Radwanska's side, however, the Pole lost 6-7(0) 6-0 6-2. Omair would now like to have a closer look at what happened there.

When Victoria Azarenka entered the Rod Laver Arena today, she had something going on in her mind, her possibility of overtaking the top spot from Caroline Wozniacki, and that thing seemed to affect her in the first set tiebreak where she could not win a single point against Agnieszka Radwanska. But from then on, it was all Azarenka and she solidified her status as title contender with this win.

Radwanska walked on to the Rod Laver Arena today with a mission of her own, she wanted to make it fifth time lucky and enter into her first Grand Slam semifinal match and it seemed that she would, after the first set. But from then on Radwanska could not keep that level and lost to the red hot Azarenka.

Radwanska, just like Wozniacki in her quarterfinal, entered the match with cleaner stats, and Azarenka, just like Kim Clijsters, entered the match with not so good stats, but both Clijsters and Azarenka emerged out of their matches as the cleaner players and winners.

AGNIESZKA RADWANSKA STATS

Radwanska entered the match with 75% points won on her first serves when they landed in and her first serve percentage did not flop, but her winning percentage on the first serve dropped dramatically, and to add to that so did her winning percentage on second serves. You can never win a match against Azarenka by winning just 29% of your second serves or 47% of your first serves. As if that was not enough, Radwanska entered the match with a positive winner-UE differential of 27, but came out of the match with a negative 15 winner-UE differential. Radwanska will have to wait for the next Grand Slam to see if she can manage to make it to the semifinals. Read more »

After showing you his numbers analysis for the quarterfinal between Caroline Wozniacki and Kim Clijsters, our stats expert Omair made another Australian Open quarterfinal preview for you, Victoria Azarenka vs. Agnieszka Radwanska.

Agnieszka Radwanska has lost a set so far at the Australian Open, while Victoria Azarenka is yet to lose more than four games in a set. Despite that, when we look at numbers, Radwanska comes out as the cleaner one.

If we look at the Grand Slam results, we see that it is the sixth quarterfinal appearance for Azarenka and fifth for Radwanska, while Radwanska has yet to move beyond the quarterfinal stage of a major tournament, Azarenka did it at last year's Wimbledon when she lost to the eventual champion, Petra Kvitova, in the semis. Interestingly, it was Azarenka's fifth Grand Slam quarterfinal appearance when she finally moved beyond the quarterfinal stage, and this is Radwanska's fifth quarterfinal appearance. Azarenka and Radwanska are friends – will Radwanska follow in the footsteps of her friend and make it fifth time lucky or will she fade away, only time will tell us.

If we look at their head-to-head record, Azarenka has won six of their nine encounters and their latest coming at this year's Sydney in the semifinal, where Azarenka won in three sets.

Let us have a look at what the numbers suggest about their form so far at the Australian Open.

When we look at numbers, they are quite close in almost all departments. However, Azarenka has an upper hand by a huge margin in the 2nd serve winning percentage, but she also has a huge number of double faults, averaging at 4+ per match so far in the tournament (equal to Kim Clijsters' double faults). Read more »

Dear readers, our now already famous stats expert Omair couldn't resist the urge and found time in his busy schedule to analyse the upcoming Australian Open quarterfinal between Kim Clijsters and Caroline Wozniacki. Numbers speak in Wozniacki's favor, but is everything in numbers? Let's see if we can conclude something.

There are so many things you plan on doing, but you you never get to complete them. That is what happened with me, when I had planned on making a probability analysis for the Australian Open 2012, it never got complete and then I got heck of busy. Being an audit trainee no doubt has its perks of excessive late sittings and no weekends, but I just could not resist my urge to analyse the Australian Open quarterfinals, using the performance of the quarterfinalists so far in the tournament. I will be using the stats to look into the quarterfinal showing, as to who has a better shot at making the semis. Let's first analyse Kim Clijsters and Caroline Wozniacki.

Kim got her ankle twisted in her fourth round epic battle against Li Na. Wozniacki won't get a better chance than this to avenge her previous losses to the former world No. 1, after all it was Clijsters who denied Wozniacki the taste of her first major when she beat the Dane in the US Open final in 2009.

Wozniacki has yet to lose a set in this tournament, while Clijsters has already lost one to Li, and was on the brink of defeat in straight sets but turned it around to emerge as a winner. Thousand dollar questions are: Will Clijsters' ankle hold to let her complete in the last Australian Open of her career? Will Clijsters have enough in tank to battle past Wozniacki who has no doubt the best defensive skills at the moment?

Clijsters is 2-0 against Wozniacki, but their last meeting at the year-end Championships in 2010 went the distance. Let us have a look at what the numbers say when we see each player's first four matches at the Aussie Open 2012:

Wozniacki has +8% advantage in the first serves, but what is important is that although Wozniacki has higher 1st serve percentage, Clijsters' 1st serve winning percentage is much higher than Wozniacki's, but so are her double faults. Clijsters has been serving 4+ double faults on average in each match so far, which means losing her serve at least once in each match by only double faults.

What is more worrying is Clijsters' ratio of winners and unforced errors. If you look at the number of winners, Wozniacki is not far behind, but if you look at the number of unforced errors Wozniacki comes out as a cleaner one by a huge margin. Clijsters has a differential of negative 24, whereas Wozniacki has a positive differential of 4. Break point conversion rate, receiving points won percentage again go in Wozniacki's favour. The department where Wozniacki lags is the points won at net. While Clijsters has lost only one point out of her 18 net trips (95%), Wozniacki managed to win only 68% of her net trips. Read more »