Former tennis player Monica Seles, winner of nine Grand Slams, has revealed that she has suffered from 'myasthenia gravis' for three years, a neuromuscular disease that weakens the muscles.

At 51 years old, the player of Yugoslavian origin, but naturalized American, decided to talk about her illness just days before the start of the US Open to raise awareness about this condition.

"I was playing tennis with some children or with some relatives and I missed a ball. It was like I was seeing two balls. They were symptoms that I couldn't ignore. It took me time to absorb them and be able to talk openly about it, because it is something very difficult. It affects me a lot on a daily basis," Seles said in an interview with the AP news agency.

Seles won eight Grand Slams between the ages of 16 and 19, but suffered a knife attack in Hamburg in 1993, while He was playing a match that kept him off the court for two years, and he only won one more major after that incident. He retired permanently in 2003, with 53 titles under his belt and 178 weeks at the top of the rankings.

What is myasthenia gravis?

Myasthenia gravis has no cure and gradually weakens the muscles that control movement of the eyes, face, jaw, throat and limbs, which can affect the ability to speak, swallow, breathe and perform other daily activities.