Stadium: Show Court 6 Round: 54 Ground: Clay
| ITF M25 Marburg | 2021/07/05 13:55 | Dominik Recek v Karlo Cubelic | 6-4,6-2 |
| ITF M15 Antalya | 2021/06/06 07:30 | Karlo Cubelic v Vitali Shvets | 5-7,6-4,3-10 |
| ITF M15 Jerusalem | 2021/05/13 07:00 | Karlo Cubelic v Felix Corwin | 2-6,0-6 |
| ITF M15 Jerusalem | 2021/05/12 12:00 | Roi Ginat v Karlo Cubelic | 1-6,3-6 |
| ITF M15 Jerusalem | 2021/05/11 06:30 | Karlo Cubelic v Charles Minc | 5-7,6-4,10-5 |
| ITF M15 Jerusalem | 2021/05/10 07:00 | Karlo Cubelic v Stefan Simeunovic | 6-1,6-1 |
| ITF M15 Ramat Hasharon | 2021/05/04 07:00 | Karlo Cubelic v Bradley Paliska | 4-6,4-6 |
| ITF M15 Ramat Hasharon | 2021/05/03 07:00 | Karlo Cubelic v Ofek Amoyal | 6-3,6-3 |
| UTR Pro Tennis Series Mulheim | 2021/07/30 13:30 | Hazem Naw v John Sperle | 6-4,6-2 |
| UTR Pro Tennis Series Mulheim | 2021/07/30 07:00 | Hendrik Jebens v John Sperle | 4-6,6-7 |
| UTR Pro Tennis Series Mulheim | 2021/07/29 08:30 | Marvin Schaber v John Sperle | 2-6,2-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/28 12:00 | Tim Gennes v John Sperle | 1-6,3-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/26 12:30 | Vasile Antonescu v John Sperle | 6-3,5-2 |
| ITF M15 Antalya | 2021/05/31 08:30 | Daniel Antonio Nunez v John Sperle | 6-4,7-5 |
| ITF M15 Antalya | 2021/05/23 07:00 | John Sperle v Jip Van Assendelft | 5-7,7-5,4-10 |
| ITF M15 Troisdorf | 2021/05/11 10:15 | John Sperle v Aliaksandr Bulitski | 6-2,4-6,5-10 |