| Open d'Australie | 01/10 14:25 | 60 | [338] de Greef, Arthur v Mohamed Safwat [153] | 2-6,4-6 | |
| Alicante, Spain | 10/11 10:30 | 164 | [252] Jaziri, Malek v de Greef, Arthur [327] | 6-0,6-3 | |
| Alicante, Spain | 10/10 14:40 | 64 | [327] de Greef, Arthur v Vit Kopriva [323] | 6-2,6-3 | |
| ITF M25 Pardubice | 09/30 13:00 | 25 | [363] Petr Nouza v de Greef, Arthur [327] | 6-3,6-4 | |
| French Open, Paris, France | 09/21 09:35 | 14 | [324] de Greef, Arthur v Robredo, Tommy [223] | 4-6,2-6 | |
| Iasi, Romania | 09/15 12:05 | 25 | [324] de Greef, Arthur v Francisco Cerundolo [237] | 1-6,4-6 | |
| German Masters | 08/28 08:15 | - | [317] de Greef, Arthur v Benjamin Lock [416] | 6-3,6-0 | |
| German Premier League | 08/27 14:05 | - | de Greef, Arthur v Netuschil, Marvin | 3-6,0-6 | |
| German Premier League | 08/26 10:10 | 1 | de Greef, Arthur v Stefan Palosi | 7-6,3-6,6-4 | |
| German Premier League | 08/25 10:20 | 1 | de Greef, Arthur v Henri Squire | 6-1,6-3 | |
| German Masters | 08/24 17:20 | 1 | de Greef, Arthur v Neal Lasowski | 6-1,6-0 | |
| Challenger Prague 2 | 08/23 10:35 | 24 | [229] Zdenek Kolar v de Greef, Arthur [324] | 6-4,6-1 | |
| Challenger - Prague | 08/18 12:50 | 25 | [324] de Greef, Arthur v Maden, Yannick [149] | 3-6,4-6 | |
| Challenger - Prague | 08/16 11:50 | 24 | [324] de Greef, Arthur v Enzo Couacaud [179] | 6-2,6-0 | |
| Nur Sultan, Kazakhstan | 03/12 08:35 | 26 | [333] de Greef, Arthur v Karatsev, Aslan [263] | Retired | |
| Nur Sultan, Kazakhstan | 03/11 05:00 | 25 | [192] Frederico Ferreira Silva v de Greef, Arthur [333] | Retired | |
| Nur Sultan, Kazakhstan | 03/10 06:00 | 24 | [333] de Greef, Arthur v Alex Molcan [291] | 6-2,2-6,6-2 | |
| Challenger - Pau | 02/24 13:05 | 24 | [331] de Greef, Arthur v Sasikumar Mukund [279] | 7-6,6-7,6-7 | |
| Bergamo, Italy | 02/18 13:05 | 25 | [235] Krstin, Pedja v de Greef, Arthur [288] | 6-2,6-4 | |
| Bergamo, Italy | 02/17 11:20 | 24 | Matteo Gigante v de Greef, Arthur | 7-6,6-7,5-7 | |
| Challenger - Cherbourg | 02/12 11:00 | 25 | [291] de Greef, Arthur v Marcora, Roberto [166] | 3-6,4-6 | |
| Challenger - Cherbourg | 02/10 17:55 | 24 | [291] de Greef, Arthur v Eriksson, Markus [304] | 6-4,6-4 | |
| Bangkok-2, Thailand | 01/20 09:10 | 24 | [268] Hugo Grenier v de Greef, Arthur [295] | 6-1,6-4 | |
| Bangkok, Thaïlande | 01/13 03:00 | 24 | [284] Alex Molcan v de Greef, Arthur [293] | 6-2,6-2 | |
| Hong Kong, Simples M-ITF-HKG-01A | 01/11 03:40 | 28 | [370] Yuta Shimizu v de Greef, Arthur [293] | 6-1,6-2 | |
| Hong Kong, Simples M-ITF-HKG-01A | 01/10 03:20 | 27 | El Midhawy, Adam v de Greef, Arthur | Retired | |
| Hong Kong, Simples M-ITF-HKG-01A | 01/09 05:05 | 26 | Coleman Wong v de Greef, Arthur | 3-6,4-6 | |
| Hong Kong, Simples M-ITF-HKG-01A | 01/08 02:00 | 25 | Ehara, Hiroyasu v de Greef, Arthur | 2-6,2-6 | |
| Wimbledon, London, Great Britain | 06/24 10:00 | 44 | [212] de Greef, Arthur v Marcos Giron [158] | 2-6,3-6 | |
| Lyon, France | 06/12 10:00 | 25 | [179] de Greef, Arthur v Ignatik, Uladzimir [263] | 6-7,6-0,6-7 |