Stadium: Court 1 Round: 25 Ground: Clay
| ITF M15 Oldenzaal | 2021/08/18 14:10 | Constantin Schmitz v Zachary Eisinga | 6-3,7-6 |
| ITF M15 Oldenzaal | 2021/08/16 10:00 | Zachary Eisinga v Aloys J W Van Baal | 3-6,6-4,10-7 |
| ITF M15 Oldenzaal | 2021/08/15 07:30 | Zachary Eisinga v Flemming Peters | 6-0,6-3 |
| ITF M25 The Hague | 2021/06/27 08:00 | Dax Donders v Zachary Eisinga | 6-2,7-5 |
| ITF M25 Alkmaar | 2021/06/21 14:25 | Guillaume Dermiens v Zachary Eisinga | 4-6,7-5,13-11 |
| ITF M25 Alkmaar | 2021/06/20 12:30 | Lodewijk Weststrate v Zachary Eisinga | 2-6,1-6 |
| ITF M15 Cairo | 2021/05/04 08:00 | Zachary Eisinga v Martin Dimitrov | 1-6,6-7 |
| ITF M15 Cairo | 2021/05/03 08:00 | Zachary Eisinga v Ali Alshati | 3-6,6-0,10-8 |
| ITF M15 Oldenzaal | 2021/08/18 08:00 | Marvin Netuschil v Mark Whitehouse | 4-6,3-6 |
| ITF M25 Marburg | 2021/07/08 11:25 | Jonathan Mridha v Marvin Netuschil | 6-4,7-6 |
| ITF M25 Marburg | 2021/07/07 11:50 | Marvin Netuschil v Alejandro Gonzalez | 6-7,6-4,6-1 |
| ITF M25 The Hague | 2021/06/27 08:00 | Marvin Netuschil v Alec Deckers | 6-4,6-2 |
| ITF M15 Bergamo | 2021/06/25 10:00 | Federico Arnaboldi v Marvin Netuschil | 7-6,6-4 |
| ITF M15 Bergamo | 2021/06/24 08:00 | Marvin Netuschil v Daniele Capecchi | 6-1,6-0 |
| ITF M15 Bergamo | 2021/06/23 09:00 | Andrea Basso v Marvin Netuschil | 6-1,2-6,2-6 |
| ITF M15 Troisdorf | 2021/05/13 13:25 | Marvin Netuschil v Sebastian Fanselow | 2-6,1-6 |