Andrej Martin defeated Nikola Milojevic 6-4 6-4 in the Lisboa CH quarter-final on clay. The upset overturned the form book — Nikola Milojevic came in leading the head-to-head 2–1. That levelled the head-to-head at 2–2.
Martin A. took it in straight sets.
Andrej Martin beat Nikola Milojevic 6-4 6-4. Umpiry, "Andrej Martin vs Nikola Milojevic — Lisboa CH Quarter-final", https://umpiry.com/match/2021-09-27/martin-vs-milojevic-lisboa-ch-qf?utm_source=cite (as of 27 September 2021).