Sofia Constanza Karlau defeated Katja Markus 1-6 6-3 10-4 in the W35 Buenos Aires 1 q32 on clay. The upset overturned the form book — Katja Markus came in leading the head-to-head 1–0. Sofia Constanza Karlau claimed a first win over Katja Markus in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2024-01-21 | W35 Buenos Aires 2 | Q32 | clay | Katja Markus | 6-4 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.