Stadium: Campo 4 Round: 45 Ground: Clay
| Challenger Recanati Qual | 2018/06/30 17:25 | Zhizhen Zhang v Nikola Cacic | 6-7,6-3,6-4 |
| Challenger Almaty - Kwalifikacje | 2018/06/09 05:35 | Nikola Cacic v Renta Tokuda | 6-7,4-6 |
| Challenger Shymkent Qual | 2018/06/04 05:00 | Jurij Rodionov v Nikola Cacic | 7-6,6-7,7-6 |
| Challenger Shymkent Qual | 2018/06/03 05:50 | Nikola Cacic v Joao Menezes | 6-4,7-6 |
| Challenger Shymkent Qual | 2018/06/02 05:30 | Nikola Cacic v Marko Djokovic | 7-5,6-4 |
| Challenger Samarkand Qual | 2018/05/13 05:00 | Roman Safiullin v Nikola Cacic | 6-3,7-5 |
| Challenger Samarkand Qual | 2018/05/12 06:15 | Nikola Cacic v Denis Matsukevich | 7-5,7-6 |
| Challenger Karshi Qual | 2018/05/07 05:30 | Tristan Lamasine v Nikola Cacic | 6-4,6-1 |