Second seed Serena Williams beat one of the hottest players lately – seed No.10 Flavia Pennetta – 6-4 6-3 and reached the semifinals of the US Open where her opponent will be wildcard Kim Clijsters, the sensation of the tournament.

The defending champion Williams is 7-1 lifetime against Clijsters, and 7-0 on hardcourts, but the mother of little Jada is far from the "elephant" she used to feel like when she picked up a racquet for the first time after giving birth (Clijsters’ quote: "I felt like an elephant sometimes, just trying to move. Even two steps was terrible.")

Williams has only the greatest things to say about her next opponent:

I've seen how she has been moving. It seems like she's even faster than she was before. I was thinking maybe I should have a baby and then I'll come back faster. I have nothing but good feelings for Kim. She's such a good-hearted person. She takes tennis seriously, but life even more seriously. That's the type of person I am, too.

Despite so many victories of the 11-time Grand Slam champion Williams over Clijsters, the two are expected to provide a blockbuster semifinal. After all, Williams won the US Open in 1999, 2002 and 2008, and Clijsters won it in 2005. (photo via Sony Ericsson WTA Tour)

Belgian Kim Clijsters may be playing her first Grand Slam since the 2007 Australian Open, but has quickly assured the world that she is the player to beat on the WTA Tour. Along with teenager Melanie Oudin, tennis mom Clijsters is marking the 2009 US Open, being unranked and playing only her third tournament after a two-year-long break.

After victories over seeds number 14 and 3, Marion Bartoli and Venus Williams respectively, Clijsters sent packing yet another seed, No.18 Li Na, and remarkably reached the semifinals of the Grand Slam she won in 2005. Clijsters beat Li 6-2 6-4 in 63 minutes.

Progressing to the final four, Clijsters has equaled Zheng Jie’s Wimbledon 2008 campaign – the best performance by a women's wildcard in a Grand Slam. In addition, the former world No.1 Clijsters is expected to leap back into the Top 50.

Clijsters' opponent in the semifinals will be holder Serena Williams or in-form Italian Flavia Pennetta. (photo: Stephane Martinache)

Former world No.1 Kim Clijsters of Belgium, playing her first major and only her third tournament since returning to the Tour after a two-year-long break, crossed a big obstacle in the form of American third seed Venus Williams to progress to the quarterfinals of the 2009 US Open.

It was a strange match. The 2005 US Open champion Clijsters was winning game by game to unexpectedly bagel Williams in the first set. Then, again unexpectedly, the 2000 and 2001 US Open champion Williams bageled Clijsters in the second set. Such course of events made the third set totally unpredictable. However, in that final set Clijsters made what to proved to be a decisive break in the third game of the set, and even though Williams had two break points to level at 5-5 Clijsters held her serve and won the set 6-4.

Therefore, the final score was 6-0 0-6 6-4.

Clijsters' opponent in the quarterfinals will be No.18 seed Li Na of China, whom she leads 3-1 in career meetings. (photo via Life.com)

Former world No.1 Kim Clijsters has been having an amazing comeback, and has now upset Marion Bartoli for the second time since returning to the Tour.

The 14th-seeded Bartoli fell to Clijsters 5-7 6-1 6-2 in the second round of the US Open, less than a month after losing to the Belgian in Cincinnati.

The 26-year-old Clijsters is playing just her third event after a two-year-long break and a child birth, and has so far seen nothing but success.

Clijsters’ next opponent will be compatriot Kirsten Flipkens, ranked 93rd in the world. (photo via Sony Ericsson WTA Tour)

The 2005 US Open champion Kim Clijsters, who has received a wildcard this year, wasn’t really tested in her first-round match at the 2009 US Open and defeated  Viktoriya Kutuzova 6-1 6-1 in just 58 minutes.

The 26-year-old Clijsters is playing her third tournament after a two-year-long break and a child birth. The Belgian former world No.1 had scored victories over four Top 20 players (Marion Bartoli, Patty Schnyder, Svetlana Kuznetsova and Victoria Azarenka) in Cincinnati and Toronto, prior to this US Open.

Clijsters will most likely face world No.14 Marion Bartoli in the second round, whom she beat in Cincinnati, in the match which opened her comeback to professional tennis. (photo via Sony Ericsson WTA Tour)

Despite the deadly storm hitting Toronto, all the third-round matches at the Rogers Cup were completed and we have our quarterfinalists.

No.5 seed Jelena Jankovic ended the run of wildcard Kim Clijsters with a 1-6 6-3 7-5 victory, despite trailing 5-3 a very dramatic deciding set. Jankovic's next opponent will be Alisa Kleybanova, whom she has never faced before.

Maria Sharapova, who has advanced by beating No.7 seed Vera Zvonareva, will play No.14 seed Agnieszka Radwanska in the quarterfinals.

"I have had a lot of rain delays in my career but probably not because of a tornado," Sharapova said after the match. "It was good knowing we were around cement in the player's area."

No.4 seed Elena Dementieva defeated her third-round opponent Shahar Peer on her fifth match point and here’s her interesting post-match comment: "Losing to Jankovic in Cincinnati after having four match points, it's just not enough for me. I really need five or more. From now on, every time I have a match point and finish the game there, I'll feel lucky." Dementieva will play Samantha Stosur in the quarterfinals.

No.2 seed Serena Williams’s quarterfinal opponent will be Lucie Safarova, who followed up her second round win over No.11 seed Ana Ivanovic with a win over Zheng Jie. (source: Sony Ericsson WTA Tour, photo by our reader Colleen)

After having an amazing comeback to professional tennis at Cincinnati, Kim Clijsters has continued her winning ways.

Last week at the Western and Southern Financial Group Women’s Open, former No.1 Clijsters had defeated two Top 20 players and one Top 10 player (Marion Bartoli, Patty Schnyder and Svetlana Kuznetsova), before being stopped by current No.1 Dinara Safina in the quarterfinals.

Today at the Rogers Cup, Safina was upset in the second round, while Clijsters’ comeback keeps rolling as the Belgian defeated qualifier Elena Baltacha in the opening round and has now upset ninth seed Victoria Azarenka 7-5 4-6 6-1 in the second round.

Clijsters’ next test will be last weekend's champion Jelena Jankovic, seeded fifth, who beat Patty Schnyder 7-5 6-4 to advance to the third round. (photo via Sony Ericsson WTA Tour)

Wildcard Kim Clijsters had defeated three Top 20 players en route to the quarterfinals of the Western & Southern Financial Group Women’s Open before Russian world No.1 Dinara Safina ended the Belgian's fairytale comeback run. Final score: 6-2 7-5.

Clijsters defeated Marion Bartoli in the first round, Patty Schnyder in the second and Svetlana Kuznetsova in the third, which were her first three matches after a more than two-year-long break, but top-seeded Safina stopped the former world No.1 Clijsters from progressing further by winning only the second time in their eight encounters.

"I really felt today that Dinara played some of her best tennis that I've seen," said Clijsters, whose return after a child birth has proved to be more than promising. "I think by far that's the best she's ever played against me."

Safina will next play world No.12 Flavia Pennetta, who defeated Daniela Hantuchova in the quarterfinals one day after upsetting Venus Williams. By reaching the semis, Pennetta will have the honor of becoming the first Italian Top 10 tennis player.

The other semifinal pair will feature Russian fourth seed Elena Dementieva and Serbian fifth seed Jelena Jankovic. Dementieva defeated Caroline Wozniacki 6-2 6-1, while Jankovic lost only three games in the match against Sybille Bammer, who upset Serena Williams in the previous round. (source: ESPN, photo via Life.com)