Before Tsitsipas retired, Annacone was talking about Rune's stamina and cramping, and said something very interesting. He said it's not fitness. He says that because he's an emotional guy, "high-strung," and he hasn't yet learned to manage it, that it drains him. He started to say that he wastes energy, but corrected himself. He says he loves and admires the fire, just that he has to manage it better. Which is interesting, because when Carlos cramped up at RG v. Djoker, he said it was emotional, not physical. I guess because they're hitting the big stages so young, it's not something we see very often.