Stadium: Center Court Round: 19 Ground: Hardcourt outdoor
| Challenger Iasi | 2020/09/12 09:00 | Johannes Haerteis v Alexandar Lazarov | 3-6,5-7 |
| ITF Austria F2 | 2018/07/12 11:15 | Alexandar Lazarov v Johannes Haerteis | 3-6,2-6 |
| Challenger Manama | 2021/11/21 10:05 | Johannes Haerteis v Ammar Faleh Alhogbani | 6-2,6-1 |
| Challenger Helsinki | 2021/11/14 09:00 | Johannes Haerteis v Viktor Durasovic | 4-6,6-7 |
| Challenger Eckental | 2021/11/02 18:15 | Maxime Cressy v Johannes Haerteis | 6-7,6-4,6-3 |
| Challenger Eckental | 2021/11/01 11:15 | Johannes Haerteis v Uladzimir Ignatik | 4-6,6-2,7-6 |
| Challenger Eckental | 2021/10/31 13:30 | Lucas Miedler v Johannes Haerteis | 3-6,7-5,3-6 |
| Challenger Ismaning | 2021/10/25 11:50 | Otto Virtanen v Johannes Haerteis | 4-6,6-3,6-3 |
| Challenger Ismaning | 2021/10/24 12:35 | Johannes Haerteis v Tristan Lamasine | 6-4,6-4 |
| ITF M25 Hamburg | 2021/10/23 10:00 | Henri Squire v Johannes Haerteis | 6-4,6-4 |
| Challenger Manama | 2021/11/21 10:00 | Alexander Cozbinov v Alexandar Lazarov | 1-6,2-6 |
| Challenger Bratislava | 2021/11/07 15:55 | Alexandar Lazarov v Alexander Shevchenko | 6-4,5-7,3-6 |
| Challenger Lima | 2021/10/26 17:20 | Alejandro Tabilo v Alexandar Lazarov | 6-1,6-4 |
| Challenger Lima | 2021/10/25 17:00 | Lucas Catarina v Alexandar Lazarov | 4-6,2-6 |
| Challenger Lima | 2021/10/24 16:00 | Luca Castelnuovo v Alexandar Lazarov | 4-6,5-7 |
| Challenger Bogota | 2021/10/17 16:30 | Alexandar Lazarov v Bart Stevens | 6-1,3-6,3-6 |
| ITF M15 Sozopol | 2021/10/08 07:00 | Alexandar Lazarov v Billy Harris | 4-6,2-6 |
| ITF M15 Sozopol | 2021/10/07 07:00 | Alexandar Lazarov v Adam Jurajda | 6-1,6-4 |