Stadium: Court 1 Round: 27 Ground: Clay
| Challenger Como | 2018/08/27 15:30 | Martin Klizan v Alessandro Giannessi | 6-2,6-4 |
| Challenger Marbella | 2021/03/31 13:15 | Henri Laaksonen v Martin Klizan | 3-6,3-6 |
| Challenger Marbella | 2021/03/29 13:50 | Maxime Cressy v Martin Klizan | 1-6,6-7 |
| Challenger Biella | 2021/03/09 10:15 | Martin Klizan v Matthias Bachinger | 1-6,1-6 |
| Challenger Nur-Sultan | 2021/03/03 04:00 | Tung-Lin Wu v Martin Klizan | 6-3,4-6,7-6 |
| Challenger Nur-Sultan | 2021/02/26 07:40 | Martin Klizan v Prajnesh Gunneswaran | 3-6,6-4,4-6 |
| Challenger Nur-Sultan | 2021/02/24 11:10 | Martin Klizan v Ulises Blanch | 6-7,6-2,7-6 |
| Challenger Nur-Sultan | 2021/02/22 09:30 | Martin Klizan v Timofey Skatov | 6-4,4-6,7-6 |
| Challenger Biella | 2021/02/17 17:05 | Martin Klizan v Andreas Seppi | 6-7,3-6 |
| Challenger Marbella | 2021/03/31 11:50 | Alessandro Giannessi v Pedro Sousa | 6-4,6-3 |
| Challenger Marbella | 2021/03/29 12:00 | Joao Domingues v Alessandro Giannessi | 3-6,4-6 |
| Challenger Zadar | 2021/03/24 09:00 | Alessandro Giannessi v Nerman Fatic | 6-7,7-5,6-7 |
| Challenger Zadar | 2021/03/22 14:35 | Alessandro Giannessi v Riccardo Bonadio | 7-5,7-5 |
| Challenger Gran Canaria | 2021/03/05 16:05 | Alessandro Giannessi v Carlos Gimeno Valero | 2-6,6-4,2-6 |
| Challenger Gran Canaria | 2021/03/03 13:00 | Alessandro Giannessi v Nikolas Sanchez Izquierdo | 7-6,7-5 |
| Challenger Gran Canaria | 2021/03/02 13:05 | Alessandro Giannessi v Emilio Nava | 6-2,6-3 |
| Challenger Gran Canaria | 2021/02/24 12:00 | Steven Diez v Alessandro Giannessi | 7-6,7-6 |