The only former champion in the field, Maria Sharapova, looks somehow blocked during this week's WTA Championships and after losing to Samantha Stosur for the first time in their ten matches, the Russian fell to Li Na the following day 7-6 (4) 6-4.

The third White Group round-robin match of the tournament was long and unpredictable, as both Sharapova and Li had big ups and downs. Also, they piled up a total of 74 unforced errors, 37 each!

First it was Sharapova who led, 4-2, but then Li took charge and forced a tiebreak, their first in eighteen sets they played, and after Sharapova's 4-0 lead in the tiebreak, Li stormed to 7-4 to win the set. The second set was also undecided. At 5-2 for Li, Sharapova broke her opponent's serve, and you can never count Sharapova out. However, the Russian wasn't even close to her best and Li eventually won 7-6(4) 6-4.

The 2004 champion Sharapova is so far the biggest disappointment of the tournament, and we don't know how much of it is due to her very recent ankle injury. The former world No.1, now ranked No.2, was the biggest Caroline Wozniacki's competitor for the top ranking. All the Dane has to do now to secure her year-end top spot is to beat Vera Zvonareva in the match they've just started. (photo: Esther Lim)

The 2011 TEB BNP Paribas WTA Championships in Istanbul start tomorrow, not affected by the devastating earthquake that killed around 270 people in Turkey. Players and the Tour expressed their condolences, but their job is calling them to focus on the big task ahead.

Since only the most successful eight players of the season are in the competition, it is not entirely reasonable to talk about the toughness of the draw, but we can always speculate: is the world No.1 the favorite, or the most-established players, or the late season bloomers, or someone else? Let’s analyze the two round-robin groups.

RED GROUP: Caroline Wozniacki, Petra Kvitova, Vera Zvonareva, Agnieszka Radwanska

The tournament will start with the clash between Kvitova and Zvonareva. Kvitova is making her debut at the WTA Championships, but at this year’s Wimbledon she showed she doesn’t shy away at grand stages. Also, the Czech is fresh off a WTA title in Linz.

Another first-time qualifier, Agnieszka Radwanska, is also in action on the first day, against world No.1 Caroline Wozniacki. Radwanska is the hottest player this fall, having won 11 of her last 12 matches, including Premier-level titles in Tokyo and Beijing. Zvonareva was runner-up in Tokyo, while Wozniacki had the worst results of the group this fall, losing in the third round of Tokyo and the quarterfinals of Beijing.

To give you a deeper insight into the mutual relationships of the players, here are their head-to-head statistics, with this year's records in brackets. Read more »

This season Li Na became the first Asian to win a Grand Slam, at the Australian Open she became the first Asian Grand Slam finalist, the Chinese 29-year-old also equaled the highest ranking ever for an Asian player in June and now she became the first player from her country to qualify for the $4,900,000 season-ending Championships, which will be held in Istanbul, Turkey, October 25-30.

Three more berths in the singles field are left in Istanbul, as Caroline Wozniacki, Maria Sharapova, Petra Kvitova and Victoria Azarenka have already qualified. Azarenka, the second seed at this week’s China Open, retired from the tournament in the third round against Anastasia Pavlyuchenkova with right foot injury. (photo: © Neal Trousdale)

Since her triumph at Roland Garros Li Na has been consistent with arranging  new sponsorship deals, but her tennis results are regularly disappointing. The Chinese has recently signed on with two more sponsors, Crown (Australia's leading integrated entertainment and resort operator) and Kunlunshan (China's first mineral water brand), but when it comes to tennis, she doesn’t know what to do to help herself.

The world No.5 Li followed her US Open first round exit with a defeat in her first match at the Beijing Premier-level tournament. Against qualifier Monica Niculescu of Romania, Li was bageled in the second set and in the first set won four games, only after coming back from a 5-1 deficit.

Right now I've just lost all confidence. On the court I don't know what I can do. I felt even winning one point was tough for me. My coach came out and told me exactly what was right, but I couldn't do it.

To make things worse, Li played the semifinals of Beijing last year, so she will lose a lot of points. Niculescu, ranked 58th in the world, scored her first Top 10 win. (via WTA Tour, photo: © Neal Trousdale)

Two big stars of women’s tennis have ended cooperation with their coaches – world No.5 Li Na with Michael Mortensen who coached her since April this year, and world No.9 Kim Clijsters with her long-time coach Wim Frissette.

The main reason Li fired Danish coach Mortensen is that she felt he was giving her false encouragement and confidence.

He tells me everything is perfect, everything is fantastic. I say, ‘Yes, everything is fantastic, but I always lose first round.’ I mean, this is not fantastic. I think we need to change something. I think maybe the team or coach just try to give me confidence, but I don’t think I get [it].

The start of Li’s cooperation with Mortensen was fruitful, including her first Grand Slam title at Roland Garros, but the Chinese has since won more than one match at only one tournament.

As for Clijsters, the Belgian has replaced coach Wim Frissette with Carl Maes. Frissette was her coach from 1995 to 2002 and joined her team again earlier this season.

Clijsters is still enjoying her time off the Tour. The last tournament she played was the Rogers Cup (source: Beyond the Baseline, photos: © Neal Trousdale)