Watch: Two-time Grand Slam Champion Retires From Match In Tears After Opponent Erases Mark On Court

An incident during a tennis match between China's Zhang Shuai and Hungary's Amarissa Kiara Toth at the Budapest Open on Tuesday gave rise to a huge controversy. It started with a debatable decision that was followed by an unsportsmanlike conduct from Toth and ended with Zhang retiring from the match in tears. It started when the first set was tied at 5-5, 15-15 on Zhang's serve. The Chinese star hit a cross-court forehand shot that landed really close to the sideline and was called out.

This is so heartbreaking, she called the physio and I think she just couldn't handle the pressure and the feelings as she started crying so she retired from the match, the reaction from the crowd and especially Toth, loss for words. She didn't deserve to be treated like this pic.twitter.com/QVzqgPO7yy

The chair umpire had a look on from close distance but the decision remained unchanged. However, Zhang -- who is a two-time Grand Slam champion in women's doubles -- kept pleading for the call to be reconsidered. The Chinese tennis star even asked to speak with the tournament supervisor.

During this moment, Zhang's opponent Toth was also spotted laughing as the crowd kept mocking the Chinese player.

After the match continued for another point, Toth walked up to the mark and erased it despite Zhang asking her not to do that.

"Wait, wait, wait! Keep the mark," said Zhang. "What are you doing? Why would you do that?"

The result of the entire incident saw Zhang getting down in tears. She sat on the resting chair on the side of the court before deciding to call it quits.