China's Zhang Shuai retired from her Hungarian Grand Prix match in tears on Tuesday after her local opponent Amarissa Toth erased a ball mark on the clay court following a disputed line call. Second seed Zhang hit a crosscourt forehand that appeared to land on the line but was called out by the line judge. The chair umpire then stepped down to take a look at the mark and confirmed the ball had landed outside the line. Zhang was incensed by the call