Andreeva is guided by former world No.2 Conchita Martinez. The pair have clearly prepared thoroughly in order to reach this level.
"I feel like my coach has been helping me so much," the teenager said. "I feel like I already give her so much credit, but today she is going to get even more.
"She's been telling me all the things I need to keep an eye on and what I have to focus on. She's put a lot of work into how I played today. So, thanks to her!"
Teichmann, who previously posted a last-16 finish in Paris back in 2022, fended off two immediate break points, the second with a sweeping drive volley that was followed by a roar to her vocal support camp.