Stadium: Court 4 Round: 26 Ground: Clay
| ITF M25 Oviedo | 2021/08/31 10:00 | Johan Nikles v Federico Zeballos | 7-6,6-2 |
| Challenger Warsaw | 2021/08/25 10:30 | Johan Nikles v Jozef Kovalik | 3-6,4-6 |
| Challenger Warsaw | 2021/08/24 11:30 | Johan Nikles v Jonathan Mridha | 6-4,6-7,6-3 |
| Challenger Warsaw | 2021/08/22 13:35 | Johan Nikles v Lucas Gerch | 6-4,7-5 |
| ATP Gstaad | 2021/07/19 10:30 | Johan Nikles v Vit Kopriva | 2-6,1-6 |
| Challenger Amersfoort | 2021/07/15 18:05 | Johan Nikles v Lukas Rosol | 2-6,1-6 |
| Challenger Amersfoort | 2021/07/13 10:15 | Ryan Nijboer v Johan Nikles | 6-7,2-6 |
| Challenger Amersfoort | 2021/07/12 09:00 | Jeremy Jahn v Johan Nikles | 2-6,3-6 |
| ITF M25 Oviedo | 2021/08/31 06:55 | Francisco Andreu Garcia v Julio Cesar Porras | 5-7,2-6 |
| ITF M25 Oviedo | 2021/08/30 09:30 | Julio Cesar Porras v Rafael Mazon-Hernandez | 6-3,6-1 |
| ITF M25 Oviedo | 2021/08/29 07:55 | Julio Cesar Porras v Vitali Shvets | 4-6,6-2,10-6 |
| ITF M25 Santander | 2021/08/25 10:00 | Ivan Gakhov v Julio Cesar Porras | 6-0,6-0 |
| ITF M25 Santander | 2021/08/23 13:30 | Julio Cesar Porras v Miguel Fernando Pereira | 6-3,6-2 |
| ITF M25 Santander | 2021/08/22 11:30 | Julio Cesar Porras v Noah Lopez | 7-6,6-4 |
| Challenger Segovia | 2021/07/29 16:30 | Feliciano Lopez v Julio Cesar Porras | 6-7,6-2,6-4 |
| Challenger Segovia | 2021/07/26 14:00 | Julio Cesar Porras v Hiroki Moriya | 7-6,6-2 |