| ITF Tunisia F40 | 2018/11/10 10:00 | Lorenzo Brunetti v Lewei Cai | 6-3,6-0 |
| ITF China F13 | 2018/08/20 02:00 | Daisuke Sumizawa v Lewei Cai | 6-4,6-1 |
| ITF China F12 Qual | 2018/08/12 02:00 | Winter Meagher v Lewei Cai | 6-0,6-4 |
| ITF China F10 Qual | 2018/07/07 05:00 | Lewei Cai v Pak Long Yeung | 2-6,0-6 |
| ITF China F9 Qual | 2018/06/30 02:00 | Yifeng Fu v Lewei Cai | 3-6,7-5,6-2 |
| ITF China F8 Qual | 2018/06/03 02:00 | Lewei Cai v Kento Tagashira | 1-6,2-6 |
| ITF Turkey F14 | 2018/04/07 11:00 | Lewei Cai v Alberto Cammarata | 2-6,1-6 |
| ITF Spain F7 | 2018/03/16 12:00 | Manuel Barros v Lewei Cai | 6-1,6-2 |
| ITF Finland F4 | 2018/11/14 12:30 | Kristjan Tamm v Marc-Andrea Huesler | 2-6,1-6 |
| ITF Finland F4 | 2018/11/12 11:00 | Patrik Hartmeier v Kristjan Tamm | 4-6,7-5,6-7 |
| ITF Finland F4 | 2018/11/11 09:00 | Kristjan Tamm v Martins Rocens | 6-4,6-4 |
| ITF Finland F4 | 2018/11/10 10:35 | Kristjan Tamm v Aliaksandr Prudnikau | 6-2,6-4 |
| ITF Estonia F3 | 2018/11/06 16:25 | Remy Bertola v Kristjan Tamm | 7-6,6-4 |
| ITF Estonia F2 | 2018/10/30 15:00 | Kristjan Tamm v Luca Castelnuovo | 2-6,2-6 |
| ITF Finland F3 | 2018/08/15 08:00 | Karl Friberg v Kristjan Tamm | 6-3,6-2 |
| ITF Finland F3 | 2018/08/13 07:00 | Kristjan Tamm v George Botezan | 2-6,6-4,6-2 |