Martina Navratilova, former world No 1 and 18-time Grand Slam champion, has strongly criticized the World Anti Doping Agency (WADA) after their decision to appeal Jannik Sinner’s innocence verdict over doping case.

“This is nuts. WADA is a mess. The Chinese swimmers walk and now this? What a bad system we have,” wrote the nine-time Wimbledon champion regarding the appeal. WADA is looking for Sinner to be suspended from 1 to 2 years.

In a statement released on Sep. 29, WADA explained that they believe that “the finding of ‘no fault or negligence’ was not correct under the applicable rules.” However, they’re not seeking “a disqualification of any results, save that which has already been imposed by the tribunal of first instance.”

Sinner tested positive for low levels of clostebol, an anabolic steroid, on March 10 and 18 — during and after the Indian Wells Masters, in which he lost in quarterfinals to Carlos Alcaraz. He was investigated by the International Tennis Integrity Agency (ITIA) and was absolved of any blame by an independent tribunal, as it was disclosed last month.

The tribunal accepted Sinner’s explanation that the substance had entered his body when receiving a massage from his physio. The Italian, who went on to win the US Open, expressed his “disappointment” at WADA’s decision.

Alcaraz said he was ‘surprised’ by WADA’s decision

Sinner’s case has been the subject of speculation and conversation for the past month. However, Alcaraz wished him “the best” for the future, and was surprised that the case reopened.

“It isn’t a good sign for tennis, in general,” said Alcaraz. “It seemed like the case was close, and now, after a month, it’s open again, which is surprising,” he added. Both Sinner and Alcaraz are competing in Beijing, ahead of the Shanghai Masters.