Stadium: Court 6 Round: 54 Ground: Clay
| ITF M25 Trier | 2021/08/23 11:30 | William Ma v Amaury Raynel | 4-6,2-6 |
| ITF M25 Ueberlingen | 2021/08/16 12:30 | William Ma v Jimmy Yang | 1-6,4-6 |
| ITF M25 Frankfurt am Main | 2021/08/09 10:35 | William Ma v Yan Sabanin | 3-6,3-6 |
| ITF M25 Wetzlar | 2021/08/02 14:35 | Benito Sanchez Martinez v William Ma | 6-3,1-6,11-9 |
| ITF M25 Kottingbrunn | 2021/07/18 07:30 | Benedikt Emesz v William Ma | 6-1,6-0 |
| UTR Pro Tennis Series Canberra | 2021/04/24 00:00 | Omar Jasika v William Ma | 6-3,5-2 |
| UTR Pro Tennis Series Canberra | 2021/04/21 01:30 | William Ma v Li Tu | 2-6,3-6 |
| UTR Pro Tennis Series Canberra | 2021/04/20 01:30 | William Ma v Arjun Mehrotra | 6-3,4-6,7-6 |
| ITF M15 Huy | 2021/08/22 14:00 | Julian Peter v Joppe Van Malderen | 1-6,0-6 |
| ITF M25 Marburg | 2021/07/05 08:00 | Julian Peter v Sidane Pontjodikromo | 1-6,1-6 |
| ITF M25 Meerbusch | 2021/04/11 12:30 | Mark Owen Endler v Julian Peter | 6-1,6-0 |