Top-rated Grandmaster Koneru Humpy suffered a shock defeat at the hands of Natalia Zhukova of Ukraine in the first game of the second round of world women’s chess championship here on Wednesday.

It turned out to be a bad day in office for the highest rated girl in the fray as she could not find her rhythm and now finds herself in a must-win situation with black pieces in the return game to stay in the knockout championship.

While Humpy faces ouster threat, the other remaining Indian Grandmaster D Harika made early inroads to the pre-quarters, defeating Elina Danielian of Armenia in her first game of the second round.

At the top of the tables, defending champion Yifan Hou of China remained on course for third round appearance with an easy victory over experienced Monika Socko of Poland. The 18-year old Chinese was a picture of confidence as she thwarted the attempts for complications by Socko and recorded a smooth victory with black pieces.