Chinese tennis player Zhang suffers panic attack, retires after opponent erases ball mark

China's 34-year-old tennis player Zhang Shuai suffered panic attack and retired from Hungarian Open match after her 20-year-old Hungarian opponent Amarissa Kiara Tóth erased a ball mark. Zhang claimed the ball was in during a game when match was at 5-5 in first set. However, it was called out. "Wait...Keep the mark! What're you doing?" Zhang was heard telling Amarissa.