Physically, at times, we see that he is tired. That was the case, for example at the Australian Open. But what is amazing is his attention. His ability to fix his attention, even when it’s hard. We see him move a little less well, run a little slower, but in the attitude: he does not move. He remains focused on each point. Even if it lasts five hours, five hours, he is concentrated on every point. And that is something almost impossible to do. He is the only one I see doing that.