Stadium: Centre Court Round: 54 Ground: Clay
| Challenger Poznan Qual | 2018/06/04 08:00 | Bernabe Zapata Miralles v Jeremy Jahn | 4-6,6-3,0-6 |
| Challenger Poznan Qual | 2018/06/03 08:00 | Kacper Zuk v Jeremy Jahn | 3-6,4-6 |
| ATP Geneva Qual | 2018/05/20 10:50 | Jeremy Jahn v Lukas Rosol | 7-6,3-6,5-7 |
| ATP Geneva Qual | 2018/05/19 14:25 | Nino Serdarusic v Jeremy Jahn | 4-6,4-6 |
| Challenger Heilbronn Qual | 2018/05/14 10:00 | Benjamin Hassan v Jeremy Jahn | 6-2,2-6,6-4 |
| Challenger Heilbronn Qual | 2018/05/13 11:10 | Marc Giner v Jeremy Jahn | 3-6,5-7 |
| Challenger Rome Qual | 2018/05/05 09:20 | Corrado Summaria v Jeremy Jahn | 7-5,4-6,6-4 |
| Challenger Francavilla Qual | 2018/04/22 08:00 | Jeremy Jahn v Joris De Loore | 7-6,3-6,3-6 |
| Challenger Poznan Qual | 2018/06/04 08:00 | Ronald Slobodchikov v Guillermo Olaso | 4-6,6-3,1-6 |
| Challenger Poznan Qual | 2018/06/03 09:25 | Juan Pablo Ficovich v Guillermo Olaso | 4-6,2-6 |
| Challenger Busan Qual | 2018/05/14 02:00 | Rubin Statham v Guillermo Olaso | 6-4,6-2 |
| Challenger Busan Qual | 2018/05/13 02:00 | Thomas Fancutt v Guillermo Olaso | 1-6,5-7 |
| Challenger Busan Qual | 2018/05/12 01:00 | Jae Hwan Kim v Guillermo Olaso | 0-6,5-7 |
| Challenger Glasgow | 2018/05/04 09:30 | Lukas Lacko v Guillermo Olaso | 6-2,6-3 |
| Challenger Glasgow | 2018/05/02 13:50 | Guillermo Olaso v Lloyd Glasspool | 6-4,6-3 |
| Challenger Glasgow | 2018/04/30 11:15 | Evgeny Karlovskiy v Guillermo Olaso | 6-7,3-6 |