| Challenger Eckental | 11/04 12:55 | 26 | [136] Sebastian Korda v Haerteis, Johannes [329] | 6-2,1-6,6-1 | |
| Challenger Eckental | 11/02 18:40 | 25 | [167] Maden, Yannick v Haerteis, Johannes [329] | 2-6,6-4,3-6 | |
| Challenger Eckental | 11/01 13:15 | 164 | [314] Lukas Klein v Haerteis, Johannes [328] | 1-6,4-6 | |
| Challenger Eckental | 10/31 09:00 | 26 | Leopold Zima v Haerteis, Johannes | 0-6,3-6 | |
| Challenger Ismaning | 10/17 14:20 | 64 | [248] Hugo Grenier v Haerteis, Johannes [326] | 6-3,6-4 | |
| ITF M25 Porto | 10/01 11:30 | 26 | [355] Bega, Alessandro v Haerteis, Johannes [328] | 6-4,0-6,7-5 | |
| ITF M25 Porto | 09/30 10:30 | 25 | Emilio Nava v Haerteis, Johannes | 6-1,4-6,2-6 | |
| Challenger Sibiu | 09/24 08:00 | 27 | [349] Haerteis, Johannes v Gomez-Herrera, Carlos [430] | 3-6,7-6,2-6 | |
| Challenger Sibiu | 09/23 08:00 | 26 | [164] Arthur Rinderknech v Haerteis, Johannes [349] | 3-6,6-3,6-7 | |
| Challenger Sibiu | 09/21 11:25 | 25 | Haerteis, Johannes v Nicholas D Ionel | 7-5,6-2 | |
| Iasi, Romania | 09/12 09:00 | - | [345] Haerteis, Johannes v Alexandar Lazarov [483] | 3-6,5-7 | |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 08/18 09:35 | 25 | [305] Kacper Zuk v Haerteis, Johannes [342] | 7-5,6-3 | |
| Exo Tennis Germany Series | 08/01 08:00 | 44 | Hazem Naw v Haerteis, Johannes | 4-6,4-6 | |
| Exo Tennis Germany Series | 07/31 08:00 | 44 | Schmitz, Constantin v Haerteis, Johannes | 0-6,3-6 | |
| Exo Tennis Germany Series | 07/30 11:00 | 44 | Daniel Vishnick v Haerteis, Johannes | 5-7,4-6 | |
| Exo Tennis Germany Series | 07/29 11:10 | 44 | [486] Gelhardt, Luca v Haerteis, Johannes [342] | 4-6,3-6 | |
| Exo Tennis Germany Series | 07/28 11:15 | 44 | [342] Haerteis, Johannes v Benjamin Hassan [354] | 4-6,2-6 | |
| Exo Tennis Germany Series | 07/25 08:00 | - | Daniel Vishnick v Haerteis, Johannes | 3-6,3-6 | |
| Exo Tennis Germany Series | 07/24 08:00 | - | Schmitz, Constantin v Haerteis, Johannes | 2-6,2-6 | |
| Exo Tennis Germany Series | 07/23 11:35 | - | Djonov, Christian v Haerteis, Johannes | 0-6,2-6 | |
| Exo Tennis Germany Series | 07/22 11:55 | - | [354] Benjamin Hassan v Haerteis, Johannes [342] | 5-7,6-7 | |
| Exo Tennis Germany Series | 07/21 11:35 | - | [342] Haerteis, Johannes v Gelhardt, Luca [486] | 6-1,6-3 | |
| DTB German Pro Series | 06/26 12:00 | 1 | Max Hans Rehberg v Haerteis, Johannes | 3-6,2-6 | |
| DTB German Pro Series | 06/25 13:35 | 1 | [250] Daniel Masur v Haerteis, Johannes [342] | 6-7,6-1,5-7 | |
| DTB German Pro Series | 06/24 14:10 | 1 | Haerteis, Johannes v Max Hans Rehberg | 3-6,2-6 | |
| DTB German Pro Series | 06/23 12:00 | 1 | [133] Stebe, Cedrik-Marcel v Haerteis, Johannes [342] | 6-4,6-3 | |
| DTB German Pro Series | 06/14 13:40 | 1 | [342] Haerteis, Johannes v Torebko, Peter [334] | 3-6,3-6 | |
| DTB German Pro Series | 06/13 15:30 | 1 | [342] Haerteis, Johannes v Sebastian Fanselow [474] | 6-4,6-4 | |
| DTB German Pro Series | 06/12 14:45 | 1 | Haerteis, Johannes v Christoph Negritu | 7-6,3-6,6-2 | |
| DTB German Pro Series | 06/11 14:35 | 1 | Haerteis, Johannes v Mika Lipp | 6-0,6-0 |