Stadium: Court 3 Round: 14 Ground: Clay
| ITF M15 Monastir | 2021/05/18 08:30 | Thomas Fancutt v Guido Ivan Justo | 6-2,6-4 |
| ITF M15 Monastir | 2021/05/10 08:00 | Guido Ivan Justo v Francois Musitelli | 6-3,4-6,5-10 |
| ITF M15 Monastir | 2021/05/05 08:25 | Guido Ivan Justo v Takashi Saito | 1-6,1-6 |
| ITF M15 Monastir | 2021/04/28 08:30 | Yuta Kawahashi v Guido Ivan Justo | 6-4,6-2 |
| ITF M15 Cordoba | 2021/04/06 14:05 | Tomas Farjat v Guido Ivan Justo | 6-2,6-4 |
| ATP Acapulco | 2021/03/14 04:35 | Guido Ivan Justo v Agustin Velotti | 0-6,1-6 |
| ATP Cordoba | 2021/02/20 19:50 | Joao Menezes v Guido Ivan Justo | 6-3,7-6 |
| Challenger Concepcion | 2021/02/14 16:00 | Guido Ivan Justo v Mariano Kestelboim | 3-6,6-4,3-6 |
| UTR Pro Tennis Series Barcelona | 2021/08/07 08:30 | Kuzey Cekirge v Federico Zeballos | 6-4,4-6,7-5 |
| UTR Pro Tennis Series Barcelona | 2021/08/06 11:30 | Federico Zeballos v Pablo Carretero | 6-0,6-1 |
| UTR Pro Tennis Series Barcelona | 2021/08/04 07:00 | Federico Zeballos v Angel G Melgar | 6-4,6-4 |
| UTR Pro Tennis Series Barcelona | 2021/08/03 08:30 | Federico Zeballos v Marat Deviatiarov | 7-6,6-4 |
| UTR Pro Tennis Series Barcelona | 2021/08/02 10:00 | Jay Friend v Federico Zeballos | 1-6,0-6 |
| Challenger Segovia | 2021/07/25 09:00 | Federico Zeballos v Alexander Cozbinov | 1-6,1-6 |
| Challenger Pozoblanco | 2021/07/23 20:20 | Federico Zeballos v Gregoire Barrere | 4-6,3-6 |
| Challenger Pozoblanco | 2021/07/21 15:00 | Federico Zeballos v Filip Cristian Jianu | 7-6,6-4 |