South has capitalised on the withdrawal of Serena Williams
British number four Melanie South made the most of her unexpected opportunity at the East West Bank Classic to reach the third round in Los Angeles.
The 22-year-old lost in qualifying but earned a bye into the second round when Serena Williams withdrew injured.
South beat Czech world number 66 Petra Kvitova 6-4 6-2 and will now face Meng Yuan in the next round after the Chinese beat 16th seed Sania Mirza.
Meanwhile, top seed Jelena Jankovic had a 7-5 6-2 victory over Vania King.
Jankovic will take over the world number one ranking from fellow Serb Ana Ivanovic if she wins the title.
Playing her first match since falling in the fourth round at Wimbledon, Jankovic saved two set points in the 10th game against the unseeded American before taking control of the
Jankovic is struggling to regain full fitness since suffering a torn meniscus in her knee during the Wimbledon defeat at the end of June, but she took comfort from the fact the injury was not hurting her.
"I was little bit behind the ball and not reacting as fast and not having then right balance on my shots, but the most important thing is I don't have pain in my leg," she said.