| Challenger Playford | 01/01 06:50 | 25 | [204] de Greef, Arthur v Casper Ruud [112] | 1-6,3-6 | |
| Challenger Playford | 12/31 04:50 | 24 | [199] Stefano Napolitano v de Greef, Arthur [204] | 3-6,6-3,5-7 | |
| Challenger - Buenos Aires | 11/14 16:00 | 26 | [230] de Greef, Arthur v Andujar, Pablo [99] | 1-6,2-6 | |
| Challenger - Buenos Aires | 11/12 17:35 | 25 | [230] de Greef, Arthur v Gastao Elias [290] | 6-4,6-3 | |
| Montevideo, Uruguay | 11/06 19:20 | 25 | [239] Arguello, Facundo v de Greef, Arthur [232] | 5-7,6-3,6-3 | |
| Challenger Guayaquil | 11/02 23:15 | 28 | [255] de Greef, Arthur v Sousa, Pedro [124] | 5-7,2-6 | |
| Challenger Guayaquil | 11/01 23:15 | 27 | [65] Cuevas, Pablo v de Greef, Arthur [255] | 5-7,3-6 | |
| Challenger Guayaquil | 10/31 19:55 | 26 | [255] de Greef, Arthur v Hernandez-Fernandez, Jose [244] | 6-0,6-4 | |
| Challenger Guayaquil | 10/30 17:55 | 25 | [210] Daniel Elahi Galan v de Greef, Arthur [255] | 4-6,0-6 | |
| Challenger Lima | 10/23 19:10 | 25 | [254] de Greef, Arthur v Sousa, Pedro [138] | 3-6,3-6 | |
| Challenger - Barcelone | 10/10 11:15 | 25 | [256] de Greef, Arthur v Wang, Tak Khunn [445] | 3-6,6-3,6-7 | |
| Florence, Italy | 10/04 13:50 | 26 | [89] Lorenzo Sonego v de Greef, Arthur [246] | 6-2,5-7,6-4 | |
| Florence, Italy | 10/03 09:50 | 25 | [246] de Greef, Arthur v Jelle Sels [275] | 6-2,6-2 | |
| Florence, Italy | 10/02 08:00 | 25 | de Greef, Arthur v Vanni, Luca | Cancelled | |
| Genoa, Italy | 09/02 11:20 | 45 | [253] de Greef, Arthur v Haider-Maurer, Andreas [436] | Retired | |
| Challenger Como | 08/26 11:40 | 46 | [247] de Greef, Arthur v Gianluca Mager [300] | 4-6,6-4,1-6 | |
| Challenger Como | 08/25 15:25 | 45 | de Greef, Arthur v Di Nicola, Gianluca | 7-6,7-5 | |
| Challenger Meerbusch | 08/13 15:45 | 25 | [280] Bernabe Zapata Miralles v de Greef, Arthur [249] | 6-4,6-2 | |
| Pullach, Germany | 08/07 09:00 | 25 | [247] de Greef, Arthur v Kimmer Coppejans [297] | 2-6,7-5,1-6 | |
| Challenger Pullach Qual | 08/06 10:00 | 54 | [247] de Greef, Arthur v Gianluca Mager [339] | 4-6,6-7 | |
| Challenger Pullach Qual | 08/05 10:00 | 46 | de Greef, Arthur v Juan Pablo Paz | 6-4,3-6,6-1 | |
| Challenger Pullach Qual | 08/04 09:00 | 45 | de Greef, Arthur v Pena Lopez, Manuel | 6-7,6-3,7-5 | |
| Challenger Padova | 07/26 08:30 | 26 | [254] de Greef, Arthur v Pavic, Ante [248] | 4-6,7-6,4-6 | |
| Challenger Padova | 07/24 10:30 | 25 | [258] Arguello, Facundo v de Greef, Arthur [254] | Retired | |
| Challenger San Benedetto | 07/17 10:00 | 25 | [162] Nikola Milojevic v de Greef, Arthur [244] | 6-4,7-5 | |
| Braunchsweig, Germany | 07/13 13:00 | 28 | [117] Jozef Kovalik v de Greef, Arthur [254] | 6-2,6-3 | |
| Braunchsweig, Germany | 07/12 12:15 | 27 | [254] de Greef, Arthur v Hugo Dellien [120] | 6-4,6-1 | |
| Braunchsweig, Germany | 07/11 09:00 | 26 | [254] de Greef, Arthur v Dutra Silva, Rogerio [135] | 6-4,7-6 | |
| Braunchsweig, Germany | 07/09 14:55 | 25 | [91] Mayer, Florian (1983) v de Greef, Arthur [254] | 6-7,6-2,2-6 | |
| Wimbledon Qual | 06/25 15:40 | 44 | [256] de Greef, Arthur v Jason Kubler [147] | 1-6,2-6 |