Stadium: Pista 3 Round: 25 Ground: Hardcourt outdoor
| Challenger Ortisei | 2020/11/19 10:00 | Johannes Haerteis v Ilya Ivashka | 6-7,3-6 |
| Challenger Ortisei | 2020/11/17 09:00 | Daniel Masur v Johannes Haerteis | 3-6,7-6,3-6 |
| Challenger Ortisei | 2020/11/15 10:00 | Alexey Vatutin v Johannes Haerteis | 3-6,6-3,3-6 |
| Challenger Ortisei | 2020/11/14 09:00 | Johannes Haerteis v Viktor Galovic | 4-6,7-6,6-4 |
| Challenger Bratislava | 2020/11/08 11:00 | Johannes Haerteis v Julian Lenz | 7-6,4-6,6-7 |
| Challenger Eckental | 2020/11/04 12:55 | Sebastian Korda v Johannes Haerteis | 6-2,1-6,6-1 |
| Challenger Eckental | 2020/11/02 18:40 | Yannick Maden v Johannes Haerteis | 2-6,6-4,3-6 |
| Challenger Eckental | 2020/11/01 13:15 | Lukas Klein v Johannes Haerteis | 1-6,4-6 |
| Challenger Prague | 2021/05/02 12:00 | Tomas Martin Etcheverry v Lukas Lacko | 6-1,6-3 |
| Challenger Ostrava | 2021/04/27 08:00 | Denis Istomin v Lukas Lacko | 0-6,6-1,6-4 |
| Challenger Lugano | 2021/03/24 09:30 | Lucas Miedler v Lukas Lacko | 7-6,6-4 |
| ATP Dubai | 2021/03/13 08:30 | Radu Albot v Lukas Lacko | 3-6,6-4,6-4 |
| ATP Doha | 2021/03/07 12:30 | Lloyd Harris v Lukas Lacko | 6-4,6-3 |
| ATP Doha | 2021/03/06 09:00 | Mousa Shanan Zayed v Lukas Lacko | 1-6,1-6 |
| ATP Montpellier | 2021/02/22 09:30 | Lukas Lacko v Peter Gojowczyk | 2-6,1-6 |
| ATP Montpellier | 2021/02/21 10:00 | Kamil Majchrzak v Lukas Lacko | 6-4,4-6,4-6 |