Qualifier Roberta Vinci beat eighth seed Daniela Hantuchova in the first round of the Pan Pacific Open in Tokyo.
The Italian took advantage of five double faults by the Slovakian to record a 6-4 6-4 victory.
Fifth seed Ana Ivanovic of Serbia defeated American Shenay Perry 6-4 6-2 but sixth seed Li Na of China saw off American Lilia Osterloh 6-3 6-2.
Top seed Maria Sharapova has a bye along with 2006 winner Elena Dementieva and second seed Martina Hingis.
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