| ATP Antwerp Qual | 10/15 14:20 | 26 | [151] Mathias Bourgue v de Greef, Arthur [146] | 7-6,6-3 | |
| Challenger Almaty | 10/05 10:00 | 27 | [98] Laslo Djere v de Greef, Arthur [147] | 6-3,6-3 | |
| Challenger Almaty | 10/05 07:25 | 26 | [272] Khabibulin, Timur v de Greef, Arthur [147] | 1-6,3-6 | |
| Challenger Almaty | 10/02 04:00 | 25 | [269] Brkic, Tomislav v de Greef, Arthur [148] | 4-6,3-6 | |
| Rome II, Italy | 09/25 10:50 | 25 | [148] de Greef, Arthur v Sousa, Pedro [102] | 1-6,4-6 | |
| Challenger Alphen | 09/06 11:20 | 25 | [338] Cagnina, Julien v de Greef, Arthur [143] | Retired | |
| Challenger Manerbio | 08/24 13:15 | 26 | [142] de Greef, Arthur v Carlos Taberner [282] | 6-7,6-3,1-6 | |
| Challenger Manerbio | 08/22 10:40 | 25 | [142] de Greef, Arthur v Federico Gaio [309] | 6-3,6-4 | |
| Challenger Meerbusch | 08/15 14:00 | 25 | [226] Ojeda Lara, Ricardo v de Greef, Arthur [144] | 7-6,6-4 | |
| ATP Gstaad Qual | 07/22 08:30 | 45 | [115] de Greef, Arthur v Adrian Bodmer [451] | 6-7,2-6 | |
| ATP Bastad | 07/18 13:05 | 25 | [348] Gulbis, Ernests v de Greef, Arthur [115] | 4-6,6-3,6-2 | |
| ATP Bastad Qual | 07/17 10:45 | 46 | [115] de Greef, Arthur v Robredo, Tommy [180] | 6-4,6-2 | |
| ATP Bastad Qual | 07/16 08:00 | 45 | [116] de Greef, Arthur v Fred Simonsson [221] | 4-6,6-4,6-4 | |
| Challenger Bastad | 07/12 16:00 | 26 | [269] Elias Ymer v de Greef, Arthur [116] | 6-3,6-1 | |
| Challenger Bastad | 07/11 11:15 | 25 | [308] Hubert Hurkacz v de Greef, Arthur [116] | 6-4,3-6,3-6 | |
| Challenger Marburg | 07/07 13:35 | 28 | [167] Stebe, Cedrik-Marcel v de Greef, Arthur [116] | 6-4,6-4 | |
| Challenger Marburg | 07/06 10:00 | 27 | [116] de Greef, Arthur v Benjamin Bonzi [219] | 6-2,7-5 | |
| Challenger Marburg | 07/05 10:00 | 26 | [116] de Greef, Arthur v Gonzalez, Maximo [169] | 7-5,7-5 | |
| Challenger Marburg | 07/03 12:50 | 25 | de Greef, Arthur v Benjamin Hassan | 7-5,6-3 | |
| Milan, Italy | 06/27 12:10 | 25 | [274] Andrea Collarini v de Greef, Arthur [115] | Retired | |
| Challenger Todi | 06/23 15:00 | 27 | [113] de Greef, Arthur v Marco Cecchinato [97] | 5-7,3-6 | |
| Challenger Todi | 06/21 13:00 | 26 | [113] de Greef, Arthur v Jozef Kovalik [162] | 6-2,6-3 | |
| Challenger Todi | 06/19 14:10 | 25 | [113] de Greef, Arthur v Zekic, Miljan [227] | 6-2,6-4 | |
| Lyon, France | 06/14 08:30 | 26 | [383] Maxime Chazal v de Greef, Arthur [117] | 4-6,6-2,6-1 | |
| Lyon, France | 06/13 11:00 | 25 | [262] Jaume Munar v de Greef, Arthur [117] | Retired | |
| French Open, Paris, France | 05/29 15:40 | 23 | [25] Richard Gasquet v de Greef, Arthur [127] | 6-2,3-6,6-1,6-3 | |
| French Open Qual | 05/26 08:00 | 46 | [215] Daniel Masur v de Greef, Arthur [127] | 3-6,4-6 | |
| French Open Qual | 05/24 15:40 | 45 | [160] Gonzalez, Maximo v de Greef, Arthur [127] | 6-3,0-6,6-7 | |
| French Open Qual | 05/23 08:00 | 44 | [216] Lopez Perez v de Greef, Arthur [127] | 6-7,0-6 | |
| Challenger - Bordeaux | 05/20 13:45 | 28 | [50] Darcis, Steve v de Greef, Arthur [138] | 5-7,6-1,7-6 |