BEIJING–World number 34 Nikola Bartunkova stunned her Czech compatriot Karolina Muchova 6-3, 6-0 at the China Open on Thursday to breeze into the semi-finals. The 20-year-old sealed the win in just 66 minutes and will play either Mirra Andreeva or Ekaterina Alexandrova in the next round. Bartunkova won five consecutive games in 19 minutes in