Stadium: Court 2 Round: 62 Ground: Clay
| ITF M25 The Hague | 2021/06/27 08:00 | Dax Donders v Eisinga, Zachary | 6-2,7-5 |
| ITF M25 Alkmaar | 2021/06/21 14:25 | Dermiens, Guillaume v Eisinga, Zachary | 4-6,7-5,13-11 |
| ITF M25 Alkmaar | 2021/06/20 12:30 | Lodewijk Weststrate v Eisinga, Zachary | 2-6,1-6 |
| ITF M15 Cairo | 2021/05/04 08:00 | Eisinga, Zachary v Dimitrov, Martin | 1-6,6-7 |
| ITF M15 Cairo | 2021/05/03 08:00 | Eisinga, Zachary v Ali Alshati | 3-6,6-0,10-8 |
| ITF M15 Cairo | 2021/04/28 10:00 | Eisinga, Zachary v Shintaro Mochizuki | 4-6,2-6 |
| ITF M15 Cairo | 2021/04/19 10:30 | Eisinga, Zachary v Fares Zakaria | 2-6,6-3,3-10 |
| ITF M15 Cairo | 2021/04/18 07:00 | Eisinga, Zachary v Magnusson, Anton | 6-2,4-6,10-2 |
| Sarajevo, Singles Main, M-ITF-BIH-05A | 2021/05/30 10:30 | Galik, Matej v Peters, Flemming | 6-1,4-6,10-8 |
| ITF M25 Kiseljak | 2021/05/24 12:15 | Breut, Lilian v Peters, Flemming | 2-6,6-3,10-7 |
| ITF M25 Kiseljak | 2021/05/23 13:15 | Peters, Flemming v Maxim Krapivin | 3-6,7-5,10-6 |
| ITF M15 Troisdorf | 2021/05/10 08:00 | Peters, Flemming v Sidane Pontjodikromo | 4-6,1-6 |
| ITF M15 Troisdorf | 2021/05/09 08:00 | Maurus Malgiaritta v Peters, Flemming | 6-2,3-6,8-10 |
| ITF - M15 Antalya | 2021/05/04 07:00 | Peters, Flemming v Karl Friberg | 3-6,5-7 |
| ITF - M15 Antalya | 2021/04/25 07:00 | Peters, Flemming v Vojtech Mares | 3-6,3-6 |
| ITF M25 Meerbusch | 2021/04/11 13:30 | Alexis Boureau v Peters, Flemming | 6-7,6-3,10-8 |