The third-seeded Peer saved six of eight break points to beat the Japanese wild card.
In other matches, seventh-seeded Iveta Benesova of the Czech Republic defeated Alberta Brianti of Italy 6-1, 7-5 and American Jill Craybas overpowered Olga Savchuk of Ukraine 6-1, 6-1.
Story continues below ↓advertisement | your ad hereKimiko Date Krumm routed Japanese compatriot Aiko Nakamura 6-2, 6-0 to set up a quarterfinal against defending champion and top-seeded Samantha Stosur of Australia.
The 40-year-old Date Krumm converted six of seven break chances and needed just 52 minutes to oust Nakamura.
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