Stadium: Court Central Round: 26 Ground: Hardcourt indoor
| ITF Israel F15 Qual | 2017/11/03 09:50 | Heyman, Christopher v Mertens, Yannick | 6-7,6-3,2-6 |
| ITF Israel F15 | 2017/11/03 08:00 | Heyman, Christopher v Mertens, Yannick | 6-7,6-3,2-5 |
| France F4, Singles | 2017/03/03 09:30 | Mertens, Yannick v Heyman, Christopher | 6-4,6-4 |
| ITF - M15 Bressuire | 2019/01/15 17:30 | Heyman, Christopher v Hugo Gaston | 6-2,1-6,6-3 |
| ITF Finland F4 | 2018/11/17 12:00 | Heyman, Christopher v Tyurnev, Evgeny | 7-5,6-3 |
| ITF Finland F4 | 2018/11/16 13:00 | Heyman, Christopher v Pauwels, Maxime | 6-2,6-3 |
| ITF Finland F4 | 2018/11/15 16:35 | Heyman, Christopher v Otto Virtanen | 6-4,6-3 |
| ITF Finland F4 | 2018/11/14 11:00 | Heyman, Christopher v Seraphim, Christian | 7-5,6-3 |
| ITF Finland F4 | 2018/11/12 12:45 | Heyman, Christopher v Klimov, Philipp | 6-4,6-3 |
| ITF Germany F16 | 2018/10/26 12:00 | Heyman, Christopher v Altug Celikbilek | 1-6,4-6 |
| ITF Germany F16 | 2018/10/25 11:00 | Heyman, Christopher v Giovanni Fonio | 6-4,6-3 |
| ITF - M15 Bressuire | 2019/01/16 09:00 | Clement Tabur v Mertens, Yannick | 2-6,3-6 |
| Challenger Columbus | 2019/01/07 15:00 | Gijs Brouwer v Mertens, Yannick | 6-3,6-3 |
| Challenger Canberra 2 | 2018/10/30 04:05 | Mertens, Yannick v Rubin Statham | 3-6,7-6,5-7 |
| Challenger Traralgon | 2018/10/24 00:25 | Mertens, Yannick v Alex Bolt | 5-7,1-6 |
| Challenger Traralgon | 2018/10/23 00:30 | Mertens, Yannick v Bourchier, Harry | 6-3,6-7,7-6 |
| Antwerp, Belgium | 2018/10/14 12:50 | Granollers, Marcel v Mertens, Yannick | 6-4,6-4 |
| ITF Portugal F18 | 2018/09/30 10:00 | Gleb Sakharov v Mertens, Yannick | 7-6,6-4 |
| ITF Portugal F18 | 2018/09/29 12:25 | Cacao, Tiago v Mertens, Yannick | 4-6,1-6 |