Katerina Siniakova of the Czech Republic claimed her first singles title in three years with a commanding 6-1, 6-0 win over Ashlyn Krueger at the Japan Open on Sunday. Rybakina defends Ningbo title as top-ranked chase continues; Siniakova dominates Japan Open for a 6th career title. Katerina Siniakova of the Czech Republic claims her first singles title in three years with a dominant 6-1, 6-0 win over Ashlyn Kreuger at the Japan.