| Challenger - Shymkent | 05/10 09:30 | 25 | [295] Filip C Jianu v Sebastian Fanselow [397] | 3-6,5-7 | |
| Challenger - Shymkent | 05/09 06:00 | 19 | Sebastian Fanselow v Bogdan Ionut Apostol | Retired | |
| Challenger - Shymkent | 05/08 07:50 | 14 | Sebastian Fanselow v Dostanbek Tashbulatov | 7-6,4-6,6-4 | |
| Challenger - Aix en Provence | 05/01 12:35 | 14 | [394] Sebastian Fanselow v Mathias Bourgue [316] | 3-6,0-6 | |
| Challenger - Praag | 04/18 08:30 | 19 | [313] Lucas Miedler v Sebastian Fanselow [399] | 6-4,6-3 | |
| Challenger - Praag | 04/17 08:30 | 14 | [403] Sebastian Fanselow v Alexander Erler [395] | 6-1,7-5 | |
| Challenger - Oeiras | 04/05 12:40 | 25 | [396] Sebastian Fanselow v Gastao Elias [173] | 1-6,2-6 | |
| Challenger - Oeiras | 03/27 09:30 | 14 | [483] Noah Rubin v Sebastian Fanselow [393] | 3-6,6-4,6-3 | |
| ITF M25 Loule | 03/17 16:05 | 25 | Gauthier Onclin v Sebastian Fanselow | 6-3,6-1 | |
| ITF M25 - Portimao | 03/09 16:35 | 25 | [260] Marius Copil v Sebastian Fanselow [349] | 6-7,6-3,6-4 | |
| ITF M25 - Portimao | 03/08 10:30 | 62 | [349] Sebastian Fanselow v Neil Oberleitner [310] | 6-3,7-6 | |
| ITF M25 - Portimao | 03/07 10:00 | 62 | Sebastian Fanselow v Mikel Martinez | 5-7,6-1,10-5 | |
| ITF M25 - Portimao | 03/06 09:30 | 62 | Sebastian Fanselow v Batiste Guerra | 6-2,6-0 | |
| ITF M25 Faro | 03/04 10:00 | 26 | Sebastian Fanselow v Jumpei Yamasaki | 2-6,6-3,3-6 | |
| ITF M25 Faro | 03/02 10:00 | 25 | [346] Sebastian Fanselow v Stuart Parker [496] | 6-3,6-3 | |
| ITF M25 - Vale Do Lobo | 02/24 12:30 | 26 | Billy Harris v Sebastian Fanselow | 5-7,6-4,6-3 | |
| ITF M25 - Vale Do Lobo | 02/23 14:15 | 25 | Miguel Gomes v Sebastian Fanselow | 0-6,0-6 | |
| Challenger - Cherbourg | 02/06 17:30 | 14 | [341] Sebastian Fanselow v Jonas Forejtek [309] | 4-6,6-3,3-6 | |
| Challenger - Cleveland | 02/01 17:15 | 25 | [203] Yasutaka Uchiyama v Sebastian Fanselow [341] | 6-4,6-3 | |
| Challenger - Cleveland | 01/31 19:20 | 19 | [357] Alex Rybakov v Sebastian Fanselow [341] | 4-6,6-7 | |
| Challenger - Cleveland | 01/30 21:40 | 14 | [389] Zachary Svajda v Sebastian Fanselow [348] | 3-6,2-6 | |
| Challenger - Columbus | 01/25 23:15 | 25 | [254] Denis Istomin v Sebastian Fanselow [348] | 7-5,1-6,6-4 | |
| Challenger - Columbus | 01/24 17:15 | 19 | [282] Peter Polansky v Sebastian Fanselow [348] | 3-6,3-6 | |
| Challenger - Columbus | 01/23 20:20 | 14 | Zachary Svajda v Sebastian Fanselow | 6-2,4-6,4-6 | |
| Challenger - Forlì - Kwal. | 01/16 10:50 | 14 | [350] Sebastian Fanselow v Tristan Lamasine [288] | 4-6,6-3,3-6 | |
| Challenger - Maia | 12/17 15:00 | 27 | [118] Andrej Martin v Sebastian Fanselow [365] | 6-2,6-2 | |
| Challenger - Maia | 12/16 10:00 | 26 | [365] Sebastian Fanselow v Goncalo Oliveira [282] | 7-6,6-4 | |
| Challenger - Maia | 12/14 11:00 | 25 | Sebastian Fanselow v Fabio Coelho | 6-3,3-6,6-3 | |
| Challenger - Bari | 11/25 10:30 | 26 | [112] Oscar Otte v Sebastian Fanselow [377] | 6-3,6-7,7-5 | |
| Challenger - Bari | 11/23 09:00 | 25 | [377] Sebastian Fanselow v Dominic Stephan Stricker [241] | 4-6,6-4,7-5 |