Re: Ana Konjuh
Well, I guess we're not all created equal - many players would probably collapse if they had to play a 5 hour match, but some (Nadal, Djokovic etc.) managed to do it when necessary, even after playing long matches in previous rounds. I remember Vekic playing in long streaks back in juniors, but Ana might not be that high on stamina, who knows. Playing styles probably make a difference here too.