| Challenger Seville | 09/06 09:00 | 26 | [244] Alessandro Giannessi v Daniel Rincon [228] | 7-6,6-0 | |
| Challenger Seville | 09/04 19:50 | 25 | [82] Jaume Munar v Alessandro Giannessi [244] | 7-6,3-6,4-6 | |
| Challenger Como | 08/31 10:30 | 26 | [244] Alessandro Giannessi v Rudolf Molleker [232] | 3-6,1-6 | |
| Challenger Como | 08/29 09:00 | 25 | [199] Jelle Sels v Alessandro Giannessi [244] | 2-6,2-6 | |
| US Open | 08/24 14:00 | 15 | [245] Alessandro Giannessi v Giulio Zeppieri [137] | 3-6,4-6 | |
| US Open | 08/22 17:45 | 14 | [245] Alessandro Giannessi v Harold Mayot [211] | 7-6,7-5 | |
| Challenger San Marino | 08/02 11:00 | 26 | [234] Federico Delbonis v Alessandro Giannessi [235] | 6-3,5-7,6-1 | |
| Challenger San Marino | 07/31 17:00 | 25 | [235] Alessandro Giannessi v Moez Echargui [291] | 1-6,6-4,6-4 | |
| Challenger Trieste | 07/18 13:50 | 25 | [348] Stefano Napolitano v Alessandro Giannessi [235] | 6-4,6-2 | |
| Challenger Trieste | 07/18 08:00 | 25 | Franco Agamenone v Alessandro Giannessi | Cancelled | |
| Challenger San Benedetto | 07/11 14:50 | 25 | Alessandro Giannessi v Luciano Darderi | Cancelled | |
| Challenger Milan | 07/05 08:30 | 26 | [216] Gauthier Onclin v Alessandro Giannessi [241] | 6-4,6-1 | |
| Challenger Milan | 07/03 13:00 | 25 | [241] Alessandro Giannessi v Francesco Maestrelli [149] | 6-3,3-6,6-1 | |
| Wimbledon | 06/26 13:05 | 14 | [235] Alessandro Giannessi v Charles Broom [374] | 4-6,7-6,3-6 | |
| Challenger Parma | 06/22 11:00 | 27 | [254] Alessandro Giannessi v Alexandre Muller [103] | 6-3,3-6,1-6 | |
| Challenger Parma | 06/21 10:30 | 26 | [254] Alessandro Giannessi v Oriol Roca Batalla [306] | 6-4,6-2 | |
| Challenger Parma | 06/20 13:30 | 25 | [304] Maxime Janvier v Alessandro Giannessi [254] | 4-6,6-4,1-6 | |
| Challenger Parma | 06/20 13:30 | 25 | Fabian Marozsan v Alessandro Giannessi | Cancelled | |
| Challenger Perugia | 06/12 16:00 | 25 | [251] Matteo Gigante v Alessandro Giannessi [238] | Retired | |
| ATP Geneva | 05/21 11:20 | 19 | [230] Alessandro Giannessi v Vitaliy Sachko [282] | 5-7,2-6 | |
| ATP Geneva | 05/20 11:30 | 14 | [230] Alessandro Giannessi v Denis Yevseyev [296] | 3-6,6-4,6-2 | |
| Challenger Oeiras | 05/16 10:10 | 25 | [179] Jan Choinski v Alessandro Giannessi [230] | 6-3,4-6,6-4 | |
| Challenger Oeiras | 05/15 09:00 | 19 | [230] Alessandro Giannessi v Daniel Michalski [289] | 6-4,6-4 | |
| Challenger Oeiras | 05/14 10:25 | 14 | [230] Alessandro Giannessi v Alberto Barroso Campos [452] | 6-1,6-3 | |
| Challenger Francavilla | 05/10 11:20 | 26 | [160] Benoit Paire v Alessandro Giannessi [230] | 7-5,7-5 | |
| Challenger Francavilla | 05/09 09:00 | 25 | [230] Alessandro Giannessi v Marco Trungelliti [227] | 3-6,6-3,6-4 | |
| Challenger Cagliari | 05/04 11:45 | 26 | [246] Alessandro Giannessi v Thanasi Kokkinakis [111] | 4-6,2-6 | |
| Challenger Cagliari | 05/03 10:25 | 25 | [246] Alessandro Giannessi v Francesco Passaro [120] | 3-6,7-6,6-4 | |
| Challenger Cagliari | 05/02 08:30 | 19 | [246] Alessandro Giannessi v Alexander Erler [36] | 7-5,6-1 | |
| Challenger Florianopolis | 04/21 16:15 | 27 | [253] Alessandro Giannessi v Benjamin Hassan [295] | 6-3,4-6,6-7 |
Alessandro Giannessi (born 30 May 1990) is a professional Italian tennis player. On 24 July 2017 he reached his highest ATP singles ranking of world No. 84 while his best doubles ranking was No. 171 on 14 October 2013.
Giannessi made his Grand Slam debut at the 2016 US Open as a qualifier where he recorded his first Major win defeating Denis Kudla in five sets.
Giannessi was a singles semifinalist at the 2017 Croatia Open Umag.
At the 2021 French Open he made his debut at this Major after qualifying for the main draw with a win over Francisco Cerundolo.
At the 2022 French Open although he lost in the third round of qualifying to Sebastian Ofner he entered the main draw as a lucky loser.
He won his fourth Challenger title and first since 2019 at the 2023 Zadar Open this time with a win over Sebastian Ofner.