LONDON • Maria Sharapova has been called a "cheat" by several prominent players on the Women's Tennis Association (WTA) Tour after she tested positive for meldonium, a substance that was banned on Jan 1.

But the WTA's chief executive officer Steve Simon himself believes that the Russian star made an "honest mistake".

"She is not saying she didn't do it. She's responsible for what goes into her body and this has been a terrible, terrible mistake she made. But I remain convinced, it was an honest mistake," he told The Times of London yesterday.

Simon has not seen Sharapova since her admission more than a week ago, but he has communicated with her by text and e-mail.

"I do plan to check with her but I know she really wants to come back and play," he said.

"She does not want to end her career this way and I know she feels the mistake is on her."

Although Simon knew of Sharapova's plight a few days before the rest of the world, he admitted his reaction was the same as the majority - absolute shock.

"From my viewpoint, watching her career and from past dealings, Maria always acted with the highest level of professionalism," he said.

"She was good for women's tennis and, I repeat, I don't want to see any athlete in a similar situation. It's not positive for the game; it's terrible. But again, nobody is above the rules."

Sharapova was provisionally suspended from Saturday and will remain in the Tennis Anti-Doping Programme as it goes through its process.

Simon does not know how long that will last, nor is he prepared to speculate on the length of any resultant ban from tennis.

"It is effectively out of the WTA's hands because the process is independent and I think very healthy because the last thing we want in our sport is when the governing body is judge and jury," he said.

"We have seen the repercussions of what that can bring (in other sports) and they determine the appropriate discipline and we are 100 per cent supportive of whatever that might be."

Meanwhile, men's tennis star Rafael Nadal stepped up his attack on those who label him a drugs cheat and threatened to sue former French minister Roselyne Bachelot, who said he failed a drug test.

Nadal said on Sunday that he is seeking "justice" and will have his day in court to silence his critics.

"I'm going to sue her, and I'm going to sue everyone who's gonna comment something similar in the future, because I am tired of that," he said.

Bachelot, who served as France's sports minister between 2007 and 2010, has said that Nadal faked an injury in 2012, when he missed the final six months of the season due to knee problems, in order to hide a positive drug test.

The 14-time Grand Slam champion said on Saturday for the first time that he is going to seek "justice" and use the courts to put a stop to speculation that he ever used performance-enhancing drugs.

"I am tired about these things. I let it go a few times in the past. No more," he said, adding that he expected better of a person who was "minister of a big country and a great country like France".

Nadal has never failed a drug test in his many years on the ATP Tour.

THE TIMES, LONDON, AGENCE FRANCE-PRESSE