Zheng Qinwen faces an uphill battle to reach the main draw of the US Open after losing in the quarter-finals of the Athens Open on Friday. The Chinese tennis star threw away solid leads in both sets before losing 6-4, 6-4 to Barbora Krejcikova of the Czech Republic. Zheng now faces the real possibility that she will have to go through the qualifiers for the final grand slam of the season due to her ranking not meeting the threshold for the main draw. With the next women’s professional rankings...