Stadium: Center Court Round: 27 Ground: Carpet indoor
| ITF Germany F4 | 2015/01/30 12:00 | Ruben Bemelmans v Johannes Haerteis | 6-2,6-3 |
| ITF M15 Prague | 2019/11/06 14:40 | Oleksii Krutykh v Johannes Haerteis | 4-6,7-6,6-2 |
| Challenger Eckental | 2019/10/29 09:00 | John-Patrick Smith v Johannes Haerteis | 7-6,6-7,7-6 |
| Challenger Hamburg | 2019/10/22 08:00 | Cem Ilkel v Johannes Haerteis | 7-5,6-1 |
| Challenger Ismaning | 2019/10/17 11:00 | Zdenek Kolar v Johannes Haerteis | 6-7,6-7 |
| Challenger Ismaning | 2019/10/16 11:50 | Johannes Haerteis v Robin Haase | 6-4,6-7,7-6 |
| Challenger Ismaning | 2019/10/14 15:10 | Johannes Haerteis v Maximilian Neuchrist | 6-4,6-4 |
| Challenger Nur-Sultan 2 | 2019/10/01 04:00 | Fabien Reboul v Johannes Haerteis | 6-4,6-7,6-3 |
| Challenger Glasgow | 2019/09/18 15:05 | Johannes Haerteis v Tobias Kamke | 3-6,4-6 |
| Challenger Ann Arbor | 2020/01/08 20:20 | Ruben Bemelmans v Aleksandar Kovacevic | 2-6,4-6 |
| Challenger Bratislava | 2019/11/04 10:20 | Federico Gaio v Ruben Bemelmans | 1-6,6-4,6-3 |
| Challenger Eckental | 2019/10/29 17:40 | Ruben Bemelmans v Oscar Otte | 6-4,2-6,3-6 |
| Challenger Eckental | 2019/10/28 14:15 | Ruben Bemelmans v Aslan Karatsev | 6-2,6-3 |
| Challenger Hamburg | 2019/10/23 08:00 | Ruben Bemelmans v Elias Ymer | 7-6,6-7,3-6 |
| Challenger Hamburg | 2019/10/21 14:55 | John-Patrick Smith v Ruben Bemelmans | 5-7,4-6 |
| ATP Antwerp | 2019/10/13 14:35 | Marius Copil v Ruben Bemelmans | 6-4,6-4 |
| Challenger Nur-Sultan 2 | 2019/10/05 06:00 | Illya Marchenko v Ruben Bemelmans | 1-6,7-6,6-4 |