| Challenger Tigre | 01/04 13:00 | 25 | Luciano Emanuel Ambrogi v Alessandro Giannessi | 5-7,0-6 | |
| Challenger Maia | 11/29 13:55 | 25 | [303] Alexandar Lazarov v Alessandro Giannessi [267] | 6-3,6-4 | |
| Challenger Valencia | 11/22 09:00 | 25 | [268] Alessandro Giannessi v Nikolas S Izquierdo [263] | 2-6,4-6 | |
| Challenger Valencia | 11/21 13:55 | 19 | [268] Alessandro Giannessi v Alvaro Lopez San Martin [401] | 4-6,0-6 | |
| Challenger Valencia | 11/20 16:45 | 14 | [264] Alessandro Giannessi v Alberto Barroso Campos [395] | 7-5,6-1 | |
| Challenger Coquimbo | 10/18 14:50 | 25 | [71] Federico Coria v Alessandro Giannessi [232] | 6-4,6-2 | |
| Challenger Rio De Janeiro | 10/11 15:05 | 25 | [386] Remy Bertola v Alessandro Giannessi [232] | 6-3,6-7,6-4 | |
| Challenger Campinas | 10/05 15:15 | 26 | [233] Alessandro Giannessi v Alexandre Muller [145] | 7-5,0-6,2-6 | |
| Challenger Campinas | 10/04 16:20 | 25 | [163] Yannick Hanfmann v Alessandro Giannessi [233] | 6-4,6-7,6-7 | |
| Challenger Genova | 09/20 13:30 | 25 | [217] Alessandro Giannessi v Pablo Andujar [117] | 4-6,6-4,2-6 | |
| Challenger Como | 08/30 08:00 | 25 | [225] Alessandro Giannessi v Kenny de Schepper [359] | Retired | |
| Challenger Como | 08/30 08:00 | 25 | Alessandro Giannessi v Mariano Navone | Cancelled | |
| Challenger Santo Domingo | 08/18 18:00 | 26 | [235] Alessandro Giannessi v Pedro Cachin [88] | 1-6,2-6 | |
| Challenger Santo Domingo | 08/17 02:20 | 25 | [235] Alessandro Giannessi v Roberto Quiroz [256] | Retired | |
| Challenger San Benedetto | 07/26 19:55 | 25 | [231] Alessandro Giannessi v Giovanni Fonio [435] | 3-6,4-6 | |
| Challenger Tampere | 07/19 14:30 | 25 | [188] Nicolas Kicker v Alessandro Giannessi [206] | 6-4,6-3 | |
| Challenger Verona | 07/11 16:00 | 25 | [182] Alessandro Giannessi v Sebastian Ofner [230] | 3-6,3-6 | |
| Wimbledon | 06/20 13:40 | 14 | [190] Alessandro Giannessi v Hugo Grenier [136] | 1-6,1-6 | |
| Challenger Parma | 06/15 15:05 | 26 | [221] Jozef Kovalik v Alessandro Giannessi [203] | 6-1,6-3 | |
| Challenger Parma | 06/13 12:30 | 25 | [205] Salvatore Caruso v Alessandro Giannessi [203] | Retired | |
| Challenger Perugia | 06/08 16:00 | 26 | [196] Alessandro Giannessi v Borna Coric [244] | 2-6,6-7 | |
| Challenger Perugia | 06/07 08:30 | 25 | [276] Nerman Fatic v Alessandro Giannessi [196] | Retired | |
| Challenger Forli | 05/31 10:30 | 25 | [173] Alessandro Giannessi v Jaume Munar [87] | 2-6,2-6 | |
| French Open | 05/23 09:00 | 23 | [173] Alessandro Giannessi v Borna Gojo [223] | 4-6,7-6,7-6,6-7,4-6 | |
| French Open | 05/19 08:00 | 19 | [173] Alessandro Giannessi v Sebastian Ofner [218] | 4-6,6-1,2-6 | |
| French Open | 05/18 08:00 | 15 | [173] Alessandro Giannessi v Thiago Agustin Tirante [192] | 7-5,6-2 | |
| French Open | 05/16 11:30 | 14 | [117] Mats Moraing v Alessandro Giannessi [173] | 6-7,0-6 | |
| Challenger Bordeaux | 05/08 10:05 | 14 | [169] Alessandro Giannessi v Matteo Martineau [392] | 2-6,6-4,4-6 | |
| Challenger Rome | 04/26 13:15 | 25 | [160] Alessandro Giannessi v Denis Yevseyev [345] | Retired | |
| Challenger Madrid | 04/12 14:30 | 25 | [164] Alessandro Giannessi v Marco Trungelliti [194] | 2-6,6-2,3-6 |
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.