Second seed Jelena Jankovic edged sixth-seeded Venus Williams 6-7(8) 7-5 6-2, improved to 5-3 lifetime against the American, and set up a Porsche Tennis Grand Prix final against Nadia Petrova.

Russia’s Petrova advanced to the final in Stuttgart with a 6-4 6-4 win over Belarusian Victoria Azarenka, the 19-year-old player who upset fourth seed Elena Dementieva in the quarterfinals.

Jankovic, who was already assured of becoming the new women's world No.1 when the rankings are released on Monday, reached her first final at the Porsche Tennis Grand Prix  (last year she was beaten in the semis by Justine Henin) and will face the 2006 Stuttgart champion Nadia Petrova.

Jankovic and Petrova meet for the eighth time in their careers and the Serb leads their series 5-2. Interestingly, two of Jankovic’s victories over Petrova came at the Porsche Tennis Grand Prix, in 2004 (first round) and 2007 (quarterfinals). (photos: Getty Images)

Semifinalists of the Porsche Tennis Grand Prix are set. Victoria Azarenka will play Nadia Petrova, while sixth seed Venus Williams will face second-seeded Jelena Jankovic. Read more »

Second seed Jelena Jankovic and sixth seed Venus Williams advanced to the quarterfinals of the Porsche Tennis Grand Prix in Stuttgart.

Williams served 12 aces on her way to a 6-4 6-2 victory over Ukraine’s qualifier Kateryna Bondarenko.

Jelena Jankovic, who will regain the world number one spot from Serena Williams, beat Kateryna’s older sister Alona Bondarenko 6-2 6-0 to win her opening match in Stuttgart.

Other quarterfinalists in Stuttgart:

Third seed Dinara Safina, one of four Russian quarterfinalists at the Porsche Tennis Grand Prix, beat Bulgaria's Tsvetana Pironkova 6-1 7-6(6) to reach the last eight. She will next play Venus Williams.

Russian seventh seed Vera Zvonareva spoiled Marion Bartoli's 24th birthday beating her 6-2 6-0, while another Russian Nadia Petrova defeated Swiss Patty Schnyder 6-4 6-1. Zvonareva’s next opponent will be Jelena Jankovic, and Petrova’s Li Na of China.

There is one more quarterfinal pair, fourth seed Elena Dementieva will play Belorussian Victoria Azarenka. (photos: Getty Images)

Serena Williams lost to China’s Li Na in the second round of the Porsche Tennis Grand Prix in Stuttgart, and consequently Jelena Jankovic will take over her No.1 ranking next week.

American Williams was defeated in an intense three-setter 0-6 6-1 6-4.

Williams only took over the top spot when she beat Jankovic in the final of the US Open three weeks ago. Since Justine Henin retired in May, as much as four players have held the No.1 ranking: Ana Ivanovic, Jelena Jankovic, Maria Sharapova and Serena Williams – and we know Henin’s coach Carlos Rodriguez is not pleased with such a state of women’s tennis.

The world No.30 Li also beat Serena’s sister Venus Williams to reach the semifinals at the Beijing Olympics. (photo via Yahoo)

Svetlana Kuznetsova and Daniela Hantuchova lost on the third day of the Porsche Tennis Grand Prix in Stuttgart.

The fifth-seeded Kuznetsova was beaten by Patty Schnyder for the first time in more than three years. Schnyder advanced into the second round with a 6-4 4-6 7-5 victory over the Russian.

Slovakia’s Daniela Hantuchova, runner-up in Stuttgart in 2002, lost 6-3 6-2 in the first round to seventh-seeded Vera Zvonareva of Russia.

Schnyder, who is seeking her second title of the year after winning in Bali, will face Russian Nadia Petrova in the second round of the Porsche Tennis Grand Prix. The Olympic bronze medalist Zvonareva will next face Marion Bartoli of France. (photo: hantuchova-daniela.com)