Osaka had said then she would boycott news conferences to raise awareness of players' mental well-being, but she did speak to reporters after the defeat by Vondrousova.
It's something incredible for me. It's something that I've been dreaming of all my life, being here and even more so beating the world number one. I'm super, super happy
Zidansek advanced 7-5, 4-6, 8-6 and will play Kazakh 21st seed Elena Rybakina or 31st-seeded Anastasia Pavlyuchenkova of Russia for a place in Saturday's final.
The 23-year-old's win over the world number 11 was her third against a player in the top 20 following her victories over Bencic and Barty in her run to the semi-finals in Charleston a month ago.