Rybarikova, ranked 43rd in the world, earned a semifinal berth for the third time this year. She ousted Kerber 7-6 (7-0), 3-6, 6-3 and will next meet third-seeded Ekaterina Makarova.
Makarova moved into the semifinals when Monica Niculescu retired with an injury during the first set of their match.
Rybarikova played in the semifinals earlier this year in Memphis and at a Wimbledon tune-up event in Birmingham, England. She lost both times and also lost in the first round of her two most recent WTA appearances.
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