Stadium: Opatija 1 Round: 25 Ground: Clay
| ITF Croatia F3 | 2018/03/20 09:00 | Kai Lemstra v Marcell Bartakovics | 6-0,3-6,6-1 |
| ITF Croatia F3 | 2018/03/19 12:30 | Kai Lemstra v Edoardo Pompei | 6-1,2-6,7-6 |
| ITF Croatia F3 | 2018/03/19 09:00 | Kai Lemstra v Michelangelo Endrizzi | 6-3,6-4 |
| ITF Croatia F2 | 2018/03/14 09:00 | Kai Lemstra v Bruno Santanna | 3-6,3-6 |
| ITF Croatia F2 | 2018/03/13 08:00 | Kai Lemstra v Valentin Royer | 1-6,6-4,6-3 |
| ITF Croatia F2 | 2018/03/11 08:00 | Kai Lemstra v Marco De Rosa | 6-2,6-3 |
| ITF Croatia F1 | 2018/03/07 09:00 | Anze Arh v Kai Lemstra | 7-5,6-1 |
| ITF Germany F3 Qual | 2018/01/29 16:30 | Dominik Boehler v Kai Lemstra | 7-6,7-6 |
| ITF Croatia F2 | 2018/03/13 11:50 | Xin Hu v Jeremy Jahn | 1-6,2-6 |
| ITF China F14 Qual | 2017/07/22 02:00 | Xin Hu v Hu Liu | 0-6,1-6 |
| ITF China F12 Qual | 2017/07/08 05:00 | Ruikai Wang v Xin Hu | 6-3,6-0 |
| ITF China F11 Qual | 2017/07/01 08:20 | Olly Sadler v Xin Hu | 6-2,5-7,6-3 |
| ITF China F9 Qual | 2017/05/30 02:00 | Chukang Wang v Xin Hu | 6-0,6-0 |
| ITF China F9 Qual | 2017/05/29 03:20 | Xin Hu v Chenhe Li | 6-2,7-6 |
| ITF China F7 Qual | 2017/05/14 01:30 | Xin Hu v Rhett Purcell | 3-6,2-6 |
| ITF China F6 Qual | 2017/05/06 04:30 | Wei Cai v Xin Hu | 7-5,6-4 |