Stadium: Hard 20 Round: 27 Ground: Hardcourt outdoor
| Wimbledon | 2023/06/26 10:00 | Matteo Gigante v Harry Wendelken | 6-3,7-6 |
| Challenger Ilkley | 2023/06/20 10:30 | Sho Shimabukuro v Harry Wendelken | 6-2,6-7,6-2 |
| Challenger Nottingham | 2023/06/11 15:40 | Harry Wendelken v Alex Michelsen | 6-4,3-6,5-7 |
| Challenger Surbiton | 2023/06/06 10:00 | Bu Yunchaokete v Harry Wendelken | 7-6,7-5 |
| Challenger Surbiton | 2023/06/05 10:00 | Pierre-Hugues Herbert v Harry Wendelken | 4-6,6-7 |
| Challenger Surbiton | 2023/06/04 12:25 | Harry Wendelken v Li Tu | 7-6,6-3 |
| ITF M15 Kalmar | 2023/05/16 12:45 | Harry Wendelken v Max Dahlin | 6-4,3-6,6-7 |
| ITF M25 Nottingham | 2023/05/04 14:05 | Daniil Glinka v Harry Wendelken | 6-2,6-2 |
| ITF M15 Eindhoven | 2023/07/31 08:00 | Guy Den Heijer v Daniel De Jonge | 6-7,7-5,11-13 |
| ITF M25 Esch/Alzette | 2023/07/20 09:30 | Guy Den Heijer v David Pichler | 7-5,3-6,5-7 |
| ITF M25 Esch/Alzette | 2023/07/19 12:05 | Guy Den Heijer v Jan Sebesta | 6-7,7-6,6-3 |
| ITF M25 Esch/Alzette | 2023/07/17 15:20 | Guy Den Heijer v William Jucha | 6-4,7-5 |
| ITF M25 Esch/Alzette | 2023/07/17 08:40 | Guy Den Heijer v Mats Bredschneijder | 4-6,6-2,10-6 |
| ITF M25 Esch/Alzette | 2023/07/10 09:30 | Brian Bozemoj v Guy Den Heijer | 6-2,4-6,16-14 |
| ITF M25 The Hague | 2023/07/07 11:35 | Eric Vanshelboim v Guy Den Heijer | 6-2,6-2 |
| ITF M25 The Hague | 2023/07/06 09:00 | Fons Van Sambeek v Guy Den Heijer | 4-6,6-1,2-6 |