It was the breathing and throat that he had the most trouble with.

- The throat was catching on to me and it didn't let go. It felt like someone had run down razor blades in my throat so I had to visit a hospital in Melbourne as he was preparing for the Australian Open.

But that didn't help, but when he got back to Adelaide he had to go to the hospital again.

- It got worse and I couldn't eat and had a hard time drinking water.

The 24-year-old Australian has high potential and beat Roger Federer in Miami 2018 but missed this year's first Grand Slam in his home country due to the illness.

Thought it was due to the grass fires

- I lost ten pounds because I couldn't eat. I try to keep fit and not go crazy. I do not look too far ahead and do not want to push the body too much, Kokkinakis tells Reuters and hope that the stay during the corona pandemic can facilitate a comeback.

Injuries in especially the elbow and knees have meant that he has not reached his full potential. The highest ranking in the world ranking was number 69 from 2015.

- I tried to get back on the track at the end of December before I realized that something was wrong, and I ran out soon but I thought it could be the grass fires with all the smoke.

Söderling: "It was about second by second to survive"

Robin Söderling was at the top of his career, which ranked fourth in the world, when he won the Båstad Tournament in 2011 and then entered glandular fever darkness and then had to end career 201 after never recovering from the disease.

- I can't even explain how bad I was. Many have asked, but it is so hard to put into words. Some periods my body was so exhausted that I just slept and slept. But all of a sudden, I got heart palpitations and panic anxiety. And I could wake up in the morning, the times I could sleep well at night, and feel that “how the hell am I going to get through this day? There is not a chance ”. There was total chaos in the body. Then it was about second by second trying to survive, Söderling told in the pod "Holmgren Möter" in November 2016.

Söderling is now the Swedish Davis Cup captain.