Out of four matches played to wrap up the fourth round of the Australian Open, two were finished with players retiring. To my great disappointment, Zheng Jie and Victoria Azarenka had to give up their fight for the quarterfinal spot because of health problems.

The No.22 seed Zheng sprained her left wrist and was forced to retire trailing 4-1 in the first set against eighth seed Svetlana Kuznetsova.

As for Azarenka, No.13 seed, she won the first set against seed No.2 Serena Williams 6-3. In the second set, trailing Williams 4-2, Azarenka was visibly suffering under the hot conditions, and with tears in her eyes retired from the match due to dizziness and gastrointestinal illness.

In the other two matches, Dementieva, the fourth seed, remained undefeated in 2009, crushing No.18 seed Dominika Cibulkova 6-2 6-2, while Carla Suarez Navarro won an all-Spanish encounter against No.21 seed Anabel Medina Garrigues 6-3 6-2. Suarez Navarro upset one of the favorites for the title Venus Williams in the second round, coming back from 5-2 down in the third set and saving match points to win the match.

American Serena Williams will meet Kuznetsova in the quarterfinals, and is 4-1 against the Russian, while Dementieva will play Suarez Navarro for the first time in her career. (source: Sony Ericsson WTA Tour, photos: Getty Images)

Wildcard competitor Jelena Dokic, ranked 187th in the world, is making her comeback even more wonderful than anyone could have imagined, and to make things better, everything’s happening at her home Grand Slam, the Australian Open. Inspired by her brilliant run and beautiful emotional post-match interviews, I decided to make this little special.

I will start with ESPN’s short story about the 25-year-old Jelena’s life and career.

At the 2009 Australian Open, the former world No.4 Dokic first defeated world No.80 Tamira Paszek, then upset No.18 Anna Chakvetadze, the amazing story continued with a defeat of No.12 Caroline Wozniacki, and No.31 Alisa Kleybanova. Dokic has reached the quarterfinals of the Australian Open and will next face powerful third seed Dinara Safina.

Dokic's post-match interview after her first-round win was the most emotional, as she talked about all the difficulties she went through. Read more »

Maria Sharapova may be falling out of the Top 10 of the WTA Tour rankings, but injured or not, she’ll always be the No.1 in marketing campaigns and fashion.

The Russian is the face of the latest advertisement for Sony Ericsson. The company is running a "Party with Maria" prize draw in a few countries across the world. Thirty lucky owners of the T303 will win a chance to meet the tennis star in Miami.

The contest is running until the end of January and you can still take part if you are in one of the following countries: France, UAE, Saudi Arabia, Kuwait/Bahrain, Jordan, and Egypt. (source: Maria Sharapova's official website)

Third seed Dinara Safina saved match points before reaching the Australian Open quarterfinals where she will face world No.187 Jelena Dokic, who has continued her dream run.

Safina beat French 15th seed Alize Cornet 6-2 2-6 7-5. Cornet surrendered a double break in the final set and two match points as the Russian dug herself out of trouble and took the win, which made Cornet slump in a chair in tears.

"Somebody needs to smack me so hard in my head that something finally shakes and I put the cables together," said the world No.3 Safina.

Australia’s comeback player Jelena Dokic continued to delight the tennis world and excite the Australian Open spectators by practically coming out of nowhere and reaching the quarterfinals. Her latest victory came over Russian 29th seed Alisa Kleybanova, who upset world No.5 Ana Ivanovic in the third round. Dokic defeated Kleybanova 7-5 5-7 8-6.

As already mentioned, one of the quarterfinals will feature Dokic and Safina. The two have actually played each other. Six years ago in Shanghai, Safina defeated Dokic 6-1 6-4. I said "actually played each other" because the 25-year-old Dokic had never before met with any of her previous opponents at the 2009 Australian Open, including Tamira Paszek, Anna Chakvetadze, Caroline Wozniacki, and Alisa Kleybanova, because of her very long absence from tennis.

In an all-Russian fourth-round match, seventh seed Vera Zvonareva set up a quarterfinal against Bartoli with a 7-5 6-4 victory over 10th seed Nadia Petrova. Bartoli crushed top seed Jelena Jankovic, who became the third Australian Open top seed in the Open Era to fall before the quarters. (via BBC, photos: Getty Images)

Seed No.16 Marion Bartoli crushed top seed and world No.1 Jelena Jankovic 6-1 6-4 in the fourth round of the Australian Open.

Bartoli’s performance was impressive. She was moving well and ruthlessly used every Jankovic’s second serve. Jankovic, on the other hand, was only occasionally coming into the match, and seemed blocked throughout.

Bartoli won the first set so fast that I thought I was dreaming. Before you knew it she was leading 5-0. Jankovic gave more resistance in the second set, coming back from a break down two times, but at 4-4 Bartoli broke once again and in the following game she earned three successive match points.

Bartoli was dominating the whole match, while Jankovic was constantly saving herself from embarrassment. I don’t know what happened to Jankovic, but the best she could do was to at least win a few games. Jankovic’s proving to everyone that she can win a Grand Slam ended with a straightforward loss. Too bad.

Bartoli, who was a Brisbane finalist this year, will face either Nadia Petrova or Vera Zvonareva in the Australian Open quarterfinals. (photos: Getty Images)

As you know world number five Ana Ivanovic is no longer coached by adidas’ Sven Groeneveld, although he was helping her during the Australian Open, and she has confessed being in need of a full-time coach.

I'm looking for a coach. We have already chatted with a couple potential coaches. In the near future, I really would like to make a decision. I think it's important.

Also, without a coach for so long it's a little bit tough. You just need some direction sometimes. That's something I felt was missing in my game. Already for a while we're trying to look into some good possibilities.

Obviously, it's a hard one, so I want to make sure we get the right coach.

Ivanovic apparently changed her mind, she had been much more confident prior to the Australian Open, look what she said before:

I already do know a lot about tennis and about other players (and) I think I'm very young and maybe a full-time coach could still be very helpful. (But) at this moment, I think I can handle it the way it is.

Reminder: The fifth-seeded Ivanovic was upset by seed No.29 Alisa Kleybanova in the third round of the Australian Open. (interview: Australian Open, photo: ivanovic-ana.com)

Seed No.20 Amelie Mauresmo was dismissed my No.13 seed Victoria Azarenka 6-4 6-2, leaving Serena Williams as the only former champion in the draw.

"It's a little bit frustrating to come out with only six games today, but I did not play well enough the key points, whether it was in the first set or second set," said Mauresmo, who reached the semifinals of Brisbane two weeks back. "She played a very good match. Really intense and consistent, and not giving away many points at all."

Recent Brisbane champion Azarenka will play Serena Williams in the fourth round. They have had one meeting so far, at the 2008 Australian Open, and Williams won 6-3 6-4.

More day six results:

Svetlana Kuznetsova beat Alona Bondarenko 7-6(7) 6-4 despite hitting 68 errors, Dominika Cibulkova defeated Virginie Razzano 7-5 7-5, Zheng Jie went past Kateryna Bondarenko 6-2 6-2, Elena Dementieva bettered Samantha Stosur 7-6(6) 6-4. Other day six results we have already been mentioned. (photo: Getty Images)

Serena Williams is well on her way to continue the tradition of winning the Australian Open titles in odd-numbered years. Wasting just enough energy, the second-seeded American beat Shuai Peng of China 6-1 6-4 in the third round.

Williams made ten aces, compared to Peng’s zero, two unforced errors less than her opponent, and 29 winners to Peng’s 12.

To some up the match: The second set was much longer than the first one, and it featured five breaks of serve in all, but at no moment was Williams’ victory questioned.

The three-time Australian open champion Williams will play either No.20 seed Amelie Mauresmo or No.13 seed Victoria Azarenka in the fourth round.

So far on day six, seed No.21 Anabel Medina Garrigues beat No.12 seed Flavia Pennetta 6-4 6-1. And Carla Suarez Navarro, the shocking conqueror of Venus Williams, advanced further, defeating Maria Jose Martinez Sanchez 6-1 6-4. (photo: Getty Images)

Skipping the 2009 Australian Open will cost Maria Sharapova the spot in the Top 10.

The world number nine Sharapova has been a member of the Top 10 since July 5, 2004. However, the Russian will fall out of this elite group on the week of February 2, 2009, after 238 weeks.

The last time Sharapova ranked outside of the Top 10 was during the week of June 21, 2004 (No.15), prior to winning 2004 Wimbledon singles title. (photo: Ralf Reinecke)

Last year’s runner-up Ana Ivanovic was upset in the third round of the Australian Open, falling to seed No.29 Alisa Kleybanova 7-5 6-7(5) 6-2 in their first career meeting.

I was aware that upset was lurking fifth seed Ivanovic, but I still hate the way she lost the match. The problem with ball toss is still in Ivanovic’s game. It was painful, and all of Ivanovic’s fans who couldn’t watch the match should consider themselves lucky. The following description will give you an idea.

Ivanovic for serving for the first set at 5-3, but then managed to lose four successive games and surrender the set to Kleybanova. The second set started horrible for Ivanovic, as she lost two of her serves, and Kleybanova had a 3-0 lead. Unexpectedly, Ivanovic leveled at 3-3, and after two breaks on both sides out of the next six games, the tiebreak was played, which the Serb managed to win. I was hoping Ivanovic would get new energy because of the hard-fought second set, but that wasn’t the case. She again let Kleybanova take a 3-0 lead, but looked to be repeating the situation from the second set winning two games in a row. However, Ivanovic didn’t level this time, and Kleybanova stormed to the victory.

Alisa Kleybanova will play sensational Jelena Dokic in the fourth round. (photo: Getty Images)