Well apart from playing a very long match some 2 hours ago and playing an even longer one yesterday, she is probably mentally exhausted as well after such a monumental win. But that's just my opinion, I'd love to be wrong though.
But if you think about it Ula has had the same match today (which she lost, so probably mentally even worse) and she had to play 2 matches yesterday. Same with Aga. Plus Ana has the advantage of being younger. I think she will do well!