The semi finalists will be decided at the ASB Tennis Classic in Auckland today after four seeds were eliminated yesterday.
The defending champion Yanina Wickmayer's first up on centre court playing Romanian Simona Halep, who advanced to the top eight when seventh seed Elena Vesnina withdrew from their second round match complaining of dizziness.
China's Shuai (SCHWAY) Peng, who eliminated third seed and former US and French Open winner Svetlana Kuznetsova, plays Britain's Heather Watson.
The top seed and former world number one Maria Sharapova's plays Hungary's Greta Arn for the first time, while the nigtht match features the Ukranian wildcard Katerina Bondarenko who plays German Julia Goerges (yulia -gor-gez).
New Zealand's Marina Erakovic is back on court in doubles action.