Caroline Wozniacki recovered from a tricky situation on a sticky court at the season-ending WTA Championships in Istanbul to stay on course to end the year with the number one world tennnis ranking.
The Dane recovered to beat Pole Agnieszka Radwanska 5-7 6-2 6-4 in an energy-sapping contest at the Sinan Erdem Dome in her first round robin match.
Wozniacki plays Vera Zvonareva, who lost to Petra Kvitova 6-2 6-4 in her second round-robin match on Thursday while Radwanska will enjoy a day off after a hectic recent run.
Australian Samantha Stosur ended a career-long nine-match losing streak against Russian Maria Sharapova with a 6-1 7-5 victory in their opening match.
Li Na is the other player in Stosur's half of the draw with the top two players from each group progressing to Sunday's semi-finals.
