Zverev worried: "I need to clarify this with the doctor now".

Alexander Zverev is going through a very delicate period.

Injured at Wimbledon, he seems to be suffering since Hamburg from physical problems he doesn't even understand himself.

Beaten by a flamboyant Musetti in the quarter-finals of the Olympic Games (7-5, 7-5), the German champion was kind enough to talk about his current sensations.

Visibly preoccupied and perplexed, he explained that he was feeling very weak, without really understanding why: "It all started in Hamburg, but continued in Paris. From the second round onwards, I felt I couldn't play the way I wanted to for more than one set. I need to clarify this with the doctor now.

I need to see what's going on so I can play better for the rest of the season. When the problem comes from the sugar level in the body, then I feel slower and don't feel like training.

Here, I feel different, my head is spinning and I can see four balls coming towards me. It's like there's nothing I can do."