| Challenger Zug | 07/25 13:30 | 25 | [261] Johan Nikles v Dimitar Kuzmanov [189] | 4-6,4-6 | |
| ATP Hamburg | 07/16 10:30 | 26 | [117] Daniel Elahi Galan v Johan Nikles [256] | 6-3,6-7,6-1 | |
| Challenger Amersfoort | 07/11 09:00 | 19 | [256] Johan Nikles v Arthur Fils [346] | 2-6,6-7 | |
| Challenger Amersfoort | 07/10 10:10 | 45 | Johan Nikles v Thomaz Bellucci | 6-4,5-7,6-1 | |
| Challenger Troyes | 06/28 13:40 | 25 | [382] Francesco Maestrelli v Johan Nikles [259] | 6-1,7-5 | |
| Challenger Oeiras | 06/23 09:00 | 26 | [260] Johan Nikles v Alex Rybakov [327] | 6-4,4-6,3-6 | |
| Challenger Oeiras | 06/21 10:00 | 25 | [260] Johan Nikles v Ergi Kirkin [305] | 4-6,6-3,6-0 | |
| Challenger Bratysława | 06/09 11:15 | 26 | [146] Vit Kopriva v Johan Nikles [281] | 6-1,6-4 | |
| Challenger Bratysława | 06/07 13:55 | 25 | [255] Vitaliy Sachko v Johan Nikles [281] | 6-3,3-6,4-6 | |
| Challenger Bratysława | 06/06 10:10 | 19 | [281] Johan Nikles v Jonathan Mridha [462] | 6-2,4-6,6-2 | |
| Challenger Bratysława | 06/05 14:05 | 14 | [276] Johan Nikles v Gergely Madarasz [449] | 6-4,7-6 | |
| Challenger Poznań | 05/29 12:35 | 14 | [277] Johan Nikles v Elmar Ejupovic [419] | 3-6,4-6 |