Stadium: Court 2 Round: 26 Ground: Hardcourt indoor
| ITF M15 Selva Gardena | 2021/10/26 07:30 | Kai Lemstra v Carlo Alberto Fossati | 6-4,7-5 |
| ITF M15 Selva Gardena | 2021/10/25 08:30 | Kai Lemstra v Dominique Graf | 7-5,6-2 |
| ITF M15 Selva Gardena | 2021/10/24 10:45 | Kai Lemstra v Davide Ferrarolli | 6-4,6-3 |
| ITF M25 Hamburg | 2021/10/17 07:55 | Tom Schonenberg v Kai Lemstra | 6-2,6-2 |
| ITF M15 Monastir | 2021/08/26 07:30 | Kai Lemstra v Renta Tokuda | 2-6,2-6 |
| ITF M15 Monastir | 2021/08/25 07:30 | Hamzeh Al-Aswad v Kai Lemstra | 2-6,1-6 |
| ITF M15 Monastir | 2021/08/24 07:30 | Seita Watanabe v Kai Lemstra | 1-6,1-6 |
| ITF M15 Monastir | 2021/08/23 09:00 | Alec Beckley v Kai Lemstra | 3-6,2-6 |
| ITF M15 Selva Gardena | 2021/10/26 09:20 | Leopold Zima v Mattia Bellucci | 4-6,6-7 |
| ITF M25 Toulouse | 2021/10/22 10:00 | Li Tu v Mattia Bellucci | 6-4,6-4 |
| ITF M25 Toulouse | 2021/10/21 10:00 | Giovanni Mpetshi Perricard v Mattia Bellucci | 3-6,3-6 |
| ITF M25 Toulouse | 2021/10/20 12:00 | Mattia Bellucci v Gijs Brouwer | 7-6,6-4 |
| ITF M15 Monastir | 2021/09/16 08:00 | Gabriel Decamps v Mattia Bellucci | 6-1,6-3 |
| ITF M15 Monastir | 2021/09/15 09:10 | Alessio Zanotti v Mattia Bellucci | 4-6,6-7 |
| ITF M15 Monastir | 2021/09/10 08:00 | Dane Sweeny v Mattia Bellucci | 6-4,6-3 |
| ITF M15 Monastir | 2021/09/09 07:55 | Li Tu v Mattia Bellucci | 5-7,6-1,6-7 |