ranked Jelena Jankovic 2-6, 6-3, 6-4 on Friday in a round-robin match at the WTA Tour's season-ending Sony Ericsson Championships, while Serena Williams and Ana Ivanovic pulled out with ailments. Zvonareva and Jankovic had both secured spots in Saturday's semifinals before the match. Zvonareva will play fellow Russian Elena Dementieva, who advanced after Serena pulled out with a stomach injury. Jankovic will face Venus Williams. Spectators were not left without matches, as Serena was replaced by Russian Nadia Petrova and Poland's Agnieszka Radwanska replaced Ivanovic. Radwanska beat Svetlana Kuznetsova 6-2, 7-5. In another match Dementieva beat her compatriot Nadia Petrova 6-4, 4-6, 6-4. At No. 9, Zvonareva is the lowest-ranked player in the eight-woman field but she put on a poised performance to beat No. 1 Jankovic. She broke Jankovic at 3-3 in the third set, putting pressure on the Serb with deep groundstrokes and occasional trips to the net. The Russian's record against Jankovic improved to 4-6. Serena said a stomach muscle injury prevented her from playing against Dementieva in a match where the winner advanced to the semis. “I did feel pain last night,” the US Open champion said. “I was still in pain just getting out of bed.” Serena lost to her sister, Venus, 5-7, 6-1, 6-0 on Thursday in what she described as her worst match of the year. Serena said she felt the injury in practice Friday and that doctors had told her to rest. Serena bristled and pointed a finger at a journalist who suggested she should have played Friday despite her injury. “I should make you work out ... for like 22 years and make you have a severe stomach strain, and then tell you to play for the sponsors,” she said. “You should try it.” Ivanovic, who had no chance of advancing after losing her first two matches, withdrew earlier Friday from her match against Svetlana Kuznetsova, citing a virus. Kuznetsova had also lost her first two matches. “It's obviously very hard for me,” said Ivanovic, who turned 21 on Thursday. “Yesterday I didn't feel good and today, even worse.” The tournament features eight players divided into two groups, with the top two in each group advancing to the elimination stage. Jankovic said she was also playing with ailments, including a back problem that requires her to take painkillers before a match. “This is the last tournament of the year,” she said. “I also have problems, but I'm willing to try my best.” Serena Williams declined to say whether she would play next year at Indian Wells, California, one of the Tour's nine top tournaments. – Agencies __