Our stats analyst Omair is already famous for his statistical articles and now he's inspired Ludolf, another reader of Women's Tennis Blog and fan of tennis numbers, to contribute his take on the WTA rankings, i.e. he compared the actual rankings with the performance of players at the biggest events – Grand Slams and WTA Championships. Enjoy!

The WTA ranking does not rank properly the strength of players in the sense of the ability to win a match or a tournament. The main reason is that it is cumulative and therefore underestimates players without a sufficient number of tournaments. We need to compute an average to avoid this. Moreover, the WTA ranking considers tournaments with weights not depending on the quality of players on them.

To achive the above-mentioned goal it seems to be more appropriate to take the average result from majors and the WTA Championships, the tournaments where the best players are almost always present. By the result of a player we mean the number of her losses (including the rounds which she did not achieve), i.e. 0 for the winner, 1 for the defeated finalist, 2 for defeated semifinalists, and so on. The results for the last 52 weeks are presented in the table, completed by the WTA ranking (after the Australian Open) for comparison. (FO: French Open, W: Wimbledon, USO: US Open, WTA: WTA Championships, AO: Australian Open)

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Petra Kvitova is the hottest player of the moment with her WTA Championships title and the year can also be considered hers, as she won Wimbledon as one of her six titles in 2011. The Czech is now enjoying her career-high ranking of number two and the next season is expected to be more than bright for this 21-year-old. Now let's see how little Kvitova was handling the tennis racquet 17 years ago.

Petr, thank you for telling me about the video! Read more »

Now that the WTA Championships in Istanbul have come to a close, let's shift our attention to the Commonwealth Bank Tournament of Champions which is about to start on November 3 in Bali. The Tour actually announced the draw of the really-season-ending tournament on the day the much more important season-ending tournament commenced (how awkward is that?), but I decided to postpone the Bali talk until Istanbul finishes.

You know that in order to qualify for the event in exotic Bali you have to win an International-level WTA tournament in the ongoing season and not qualify for the WTA Championships in Istanbul which features the best eight singles players of the year. To make things even more complicated, Marion Bartoli did not qualify for Istanbul and was therefore eligible to play Bali, but as the first alternate in Istanbul she did eventually play the event because of Maria Sharapova's withdrawal. Nevertheless, Bartoli is still qualified to play Bali. Pretty messed up. But hey, let's see who's in. Read more »

World number nine Marion Bartoli came to Istanbul as a replacement of Maria Sharapova in the WTA Championships and in the sole match she played there, the 5-7 6-4 6-4 victory over eventual runner-up Victoria Azarenka, the Frenchwoman debuted an outfit of her new clothing sponsor Lotto. The deal is for three years through to 2014.

"I am pleased to have signed with Lotto, an Italian brand, and although I'm Corse of 2 generations, my name is Italian in origin," said Bartoli who infamously used to be without a clothing sponsor for four years.

The first Bartoli's Lotto outfit was a white short-sleeve shirt and a red skort.

Lotto's women's tennis stars also include Francesca Schiavone and Agnieszka Radwanska. (sources: On the Baseline, Marion Bartoli Fan Blog, photo: Life.com)

Switzerland’s Patty Schnyder retired from tennis this season after a first-round defeat at the French Open, which was her 59th appearance at a Grand Slam, and a tribute to her 17-year-long career was organized at the WTA Championships in Istanbul.

Retired tennis champion Mary Pierce handed Schnyder a career memory book, and in attendance were also Samantha Stosur, Istanbul finalist Victoria Azarenka, Katarina Srebotnik, Kveta Peschke and WTA Chairperson and CEO Stacy Allaster, whose contract with the Tour has recently been extended and she will lead women's tennis for another five years, until 2017. Read more »

Petra Kvitova crowned her 2011 season with titles at Brisbane, Paris, Madrid, Wimbledon and very recently Linz, and now she's put the icing on the cake (the icing worth $1,750,000) by winning the TEB BNP Paribas WTA Championships on her tournament debut. Kvitova's opponent in the final, Victoria Azarenka, gave significant resistance and made the final highly entertaining, but it was Kvitova who went all the way to a 7-5 4-6 6-3 victory.

Just when it seemed the first set would finish before it even warmed up, with a desperate look on her face Azarenka won her first game of the match in the sixth game and she didn't stop there. From 1-5, Azarenka broke Kvitova's serve to love two times and leveled to 5-5. Then Kvitova finally held her serve again and in the following game capitalized on her fifth set point. Read more »

Petra Kvitova finished the round-robin phase of the WTA Championships at the top position in the Red Group, with all the three matches won, while Victoria Azarenka was the leader of the White Group, and the two have now reached the $4,900,000 tournament final by beating their semifinal opponents – Kvitova rebounded to beat Samantha Stosur, Azarenka was solid against Vera Zvonareva.

The first semifinal of the day was Kvitova vs. Stosur. Even though it was Kvitova who earned an initial lead, Stosur won the first set 7-5 and had a break point to go 2-0 up in the second set. The Czech debutante at the tournament then won six of the next eight games to win the set 6-3 before going 5-0 up in the decider. Stosur did manage to get closer in the third-set score, but the match finished to Kvitova’s advantage 5-7 6-3 6-3. Read more »

Vera Zvonareva, world No.1 Caroline Wozniacki, Agnieszka Radwanska - all those tennis stars fell in straight sets to WTA Championships debutante Petra Kvitova and the Czech confidently moved into the semifinals.

From 5-1 in the first set Radwanska started losing pace and Kvitova forced a tiebreak which she won 7-4. In the second set Kvitova was up a break, 2-0, and even though Radwanska leveled to 2-2, her comeback was brief and she lost the set and the match 7-6(4) 6-3. Nevertheless, Radwanska can be proud of her end-of-the-season achievements – not only of her Premier titles at Beijing and Tokyo, but also of her overall good performance at the WTA Championships.

All the members of the final four are now confirmed: Kvitova and Vera Zvonareva from the Red Group, Victoria Azarenka and Samantha Stosur from the White Group. The semifinal schedule is first Kvitova vs. Stosur and then Azarenka vs. Zvonareva, as the organizers have just announced. (photo: Ralf Reinecke)

The 2011 year will be remembered as a landmark year in Li Na's career, as the Chinese clinched her first Grand Slam title at the French Open. However, the way she finished her participation at the season-ending WTA Championships, where only the best eight singles players from the season compete, should be forgotten. Li suffered the biggest loss in three years, falling to Samantha Stosur with a horrible scoreline of 6-1 6-0 in 66 minutes. In 2008 in Berlin Li lost to Nadia Petrova by the same scoreline.

Li has never defeated Stosur in their six meetings, four of which were in 2011, but today's defeat is the worst of the six. Just four winners and 32 unforced errors from a recent Grand Slam champion. Must be tough.

The US Open titlists Stosur has now reached her second semifinals at the WTA Championships. Last year she lost to eventual champion Kim Clijsters. This time Stosur's semifinal obstacle will be Petra Kvitova. (photo: Tidalist)

I'm regularly reviewing fashion at Grand Slams (take a look at this year's tennis outfits at the Australian Open, Roland Garros, Wimbledon and US Open) and this time I've decided to add the season-ending Championships, as another great tennis stage. The singles field at the $4,900,000 tournament this year played in Istanbul consists of eight players, so only the mere quantity of players significantly reduces the diversity of outfits. Therefore, nothing can outclass Grand Slams as the best stages for all the fashion fun, although some stars had brand new looks prepared for the WTA Championships.

Li Na and Victoria Azarenka are sporting neat outfits, but they are nothing new, we've seen them in previous tournaments. Li is wearing Nike Women's Holiday Smash Classic Top and Pleated Skort. Azarenka already gave a lot of exposure to her Nike Women's Holiday Set Point Graphic Tank and a matching skort during her run to the Luxembourg title and Tokyo semifinals.

Petra Kvitova, another Nike representative, is just like Azarenka wearing purple and grape tones. Caroline Wozniacki is wearing the best of her recent Adidas by Stella McCartney dresses, which she should've worn at the US Open, in my opinion, instead of the similar dress in white. Read more »