Hungarian tennis player Amarissa Toth said she was "extremely sorry" for her behaviour towards China's Zhang Shuai at the Budapest Open.

Zhang retired before completing the first set and left the court in tears.

"I did not think that my first ever WTA main draw success of my career would cause such a storm," Toth said.

"I am extremely sorry for what happened, I respect Zhang Shuai as a player and as a person. It was never my intention to disrespect, hurt or upset anybody.

"I was acting in the heat of the match and got caught up by my emotions and the moment. I focused on tennis, I didn't want to win like that.

"I hope that in the future I have the opportunity to sit down and talk with Zhang and tell her how badly I feel that our match ended this way."

Zhang, a former world number two in doubles, retired while trailing 6-5 in the opening set.

As she argued with the umpire on the line judge decision, Toth appeared to be laughing and the crowd booed.

The incident received widespread condemnation from the tennis world.

Subsequently, Toth was knocked out in straight sets by Ukraine's Kateryna Baindl in the last 16 on Thursday.