| Challenger Brest | 10/23 09:00 | 19 | [133] Gabriel Diallo v Geoffrey Blancaneaux [244] | 6-4,4-6,7-6 | |
| Challenger Brest | 10/22 08:00 | 14 | Gabriel Diallo v Niels Villard | 7-6,6-1 | |
| Challenger Bratislava | 10/15 13:00 | 29 | [164] Gabriel Diallo v Joris De Loore [188] | 6-0,7-5 | |
| Challenger Bratislava | 10/14 14:10 | 28 | [164] Gabriel Diallo v Martin Damm [330] | 7-6,6-2 | |
| Challenger Bratislava | 10/13 15:15 | 27 | [164] Gabriel Diallo v Lukas Klein [149] | 3-6,7-6,6-2 | |
| Challenger Bratislava | 10/12 16:30 | 26 | [72] Dominic Thiem v Gabriel Diallo [164] | 1-6,6-4,6-7 | |
| Challenger Bratislava | 10/11 09:00 | 25 | [164] Gabriel Diallo v Arthur Fery [319] | 7-5,6-1 | |
| Challenger Mouilleron le Captif | 10/02 14:20 | 25 | [166] Gabriel Diallo v Vitaliy Sachko [163] | 6-3,4-6,4-6 | |
| Challenger Orleans | 09/25 21:55 | 25 | [161] Gabriel Diallo v Giulio Zeppieri [139] | 2-6,6-2,4-6 | |
| Challenger Orleans | 09/24 08:00 | 14 | Gabriel Diallo v Tristan Lamasine | Cancelled | |
| Davis Cup | 09/16 15:15 | 2 | [158] Gabriel Diallo v Nicolas Jarry [22] | 4-6,4-6 | |
| Davis Cup | 09/14 15:50 | 2 | [158] Gabriel Diallo v Elias Ymer [175] | 6-4,6-3 | |
| Davis Cup | 09/13 15:50 | 2 | [158] Gabriel Diallo v Lorenzo Musetti [18] | 7-5,6-4 | |
| US Open | 08/23 18:40 | 14 | [148] Kimmer Coppejans v Gabriel Diallo [132] | 6-4,5-7,7-6 | |
| Challenger Winnipeg | 08/16 23:00 | 26 | [134] Gabriel Diallo v Mattia Bellucci [198] | 2-6,3-6 | |
| Challenger Winnipeg | 08/15 16:00 | 25 | [134] Gabriel Diallo v Enzo Couacaud [180] | 4-6,6-2,7-6 | |
| ATP Toronto | 08/09 19:00 | 25 | [141] Gabriel Diallo v Alex De Minaur [18] | 4-6,5-7 | |
| ATP Toronto | 08/08 21:45 | 24 | [141] Gabriel Diallo v Daniel Evans [21] | 7-6,7-5 | |
| ATP Los Cabos | 08/01 02:35 | 25 | [140] Gabriel Diallo v Gijs Brouwer [144] | 2-6,6-4,2-6 | |
| ATP Atlanta | 07/23 15:00 | 19 | [141] Gabriel Diallo v Jason Jung [277] | 6-4,5-7,6-7 | |
| ATP Atlanta | 07/22 14:00 | 14 | [141] Gabriel Diallo v Bradley Klahn [500] | 6-3,6-2 | |
| ATP Newport | 07/18 20:10 | 25 | Gabriel Diallo v Kevin Anderson | 3-6,2-6 | |
| Wimbledon | 06/28 10:00 | 15 | [254] Matteo Gigante v Gabriel Diallo [140] | 6-4,6-4 | |
| Wimbledon | 06/26 10:00 | 14 | [226] Cem Ilkel v Gabriel Diallo [140] | 3-6,6-4,1-6 | |
| Challenger Ilkley | 06/20 15:15 | 25 | [139] Gabriel Diallo v Arthur Cazaux [147] | 3-6,6-7 | |
| Challenger Nottingham | 06/16 12:50 | 27 | [181] Arthur Cazaux v Gabriel Diallo [139] | 7-6,7-5 | |
| Challenger Nottingham | 06/15 12:05 | 26 | [139] Gabriel Diallo v Alex Michelsen [257] | 3-6,7-5,6-3 | |
| Challenger Nottingham | 06/13 16:15 | 25 | [139] Gabriel Diallo v Enzo Couacaud [159] | 6-3,6-3 | |
| Challenger Surbiton | 06/09 16:45 | 27 | [146] Gabriel Diallo v Jurij Rodionov [134] | 4-6,4-6 | |
| Challenger Surbiton | 06/08 14:30 | 26 | [25] Daniel Evans v Gabriel Diallo [146] | 5-7,2-6 |