Stadium: Court 1 Ground: Hardcourt indoor
| Challenger - Sarasota | 2019/04/15 14:00 | Heliovaara, Harri v Haerteis, Johannes | 6-3,6-2 |
| Drummondville, Canada | 2020/02/17 17:45 | Haerteis, Johannes v Bourcet, Tony | 6-2,6-0 |
| ITF - M25 Nussloch | 2020/01/24 19:00 | Haerteis, Johannes v Bemelmans, Ruben | 4-6,3-6 |
| ITF - M25 Nussloch | 2020/01/23 10:55 | Giulio Zeppieri v Haerteis, Johannes | 6-3,3-6,6-7 |
| ITF - M25 Nussloch | 2020/01/22 12:50 | Aichhorn, Jakob v Haerteis, Johannes | 2-6,6-4,4-6 |
| ITF - M15 Manacor | 2020/01/15 12:35 | Haerteis, Johannes v Pablo Llamas Ruiz | 3-6,4-6 |
| ITF M15 Prague | 2019/11/06 14:40 | Oleksii Krutykh v Haerteis, Johannes | 4-6,7-6,6-2 |
| Challenger Eckental | 2019/10/29 09:00 | Smith, John-Patrick v Haerteis, Johannes | 7-6,6-7,7-6 |
| Challenger - Hambourg | 2019/10/22 08:00 | Cem Ilkel v Haerteis, Johannes | 7-5,6-1 |
| Challenger Launceston | 2020/02/03 23:00 | Heliovaara, Harri v Pervolarakis, Michail | 3-6,3-6 |
| Challenger - Burnie | 2020/01/26 23:00 | Niki, Takuto v Heliovaara, Harri | 6-4,1-6,7-6 |
| Helsinki, Finland | 2019/11/15 14:00 | Heliovaara, Harri v Ilya Ivashka | 6-3,1-6,2-6 |
| Helsinki, Finland | 2019/11/14 11:00 | Hugo Grenier v Heliovaara, Harri | 1-6,3-6 |
| Helsinki, Finland | 2019/11/13 11:00 | Heliovaara, Harri v Hiroki Moriya | 4-6,7-6,6-3 |
| Helsinki, Finland | 2019/11/11 16:10 | Dubrivnyy, Artem v Heliovaara, Harri | 3-6,2-6 |
| Playford City II, Australie | 2019/10/30 23:30 | Jay Clarke v Heliovaara, Harri | 6-4,6-3 |
| Playford City II, Australie | 2019/10/29 23:30 | Heliovaara, Harri v Mukund Sasikumar | 7-6,6-3 |