| Challenger Barcelona | 10/07 10:15 | 26 | [204] Maxime Janvier v Alessandro Giannessi [172] | 6-4,3-6,6-2 | |
| Challenger Barcelona | 10/06 08:00 | 25 | [205] Peter Polansky v Alessandro Giannessi [172] | 2-6,4-6 | |
| Challenger Barcelona | 10/06 08:00 | 25 | Steven Diez v Alessandro Giannessi | Cancelled | |
| Challenger Split | 10/02 11:00 | 27 | [172] Alessandro Giannessi v Borna Gojo [270] | 3-6,3-6 | |
| Challenger Split | 10/01 09:00 | 26 | [134] Bradley Klahn v Alessandro Giannessi [172] | Retired | |
| Challenger Split | 09/29 12:45 | 25 | [307] Nino Serdarusic v Alessandro Giannessi [172] | 4-6,4-6 | |
| French Open | 09/23 11:10 | 15 | [122] Marc Polmans v Alessandro Giannessi [171] | 5-7,6-4,6-3 | |
| French Open | 09/21 09:20 | 14 | [158] Danilo Petrovic v Alessandro Giannessi [169] | 4-6,6-7 | |
| ATP Rome | 09/12 13:30 | 14 | [97] Hugo Dellien v Alessandro Giannessi [162] | 7-5,6-4 | |
| Challenger Trieste | 08/24 10:00 | 25 | [321] Tomas Martin Etcheverry v Alessandro Giannessi [160] | 6-3,4-6,6-1 | |
| Challenger Todi | 08/19 18:30 | 26 | [130] Federico Gaio v Alessandro Giannessi [160] | 6-4,6-2 | |
| Challenger Todi | 08/17 16:50 | - | [160] Alessandro Giannessi v Maxime Janvier [191] | 6-2,6-3 | |
| ATP Rio De Janeiro | 02/15 20:35 | 64 | [175] Joao Domingues v Alessandro Giannessi [154] | Retired | |
| ATP Buenos Aires | 02/08 18:55 | 64 | [141] Alessandro Giannessi v Facundo Bagnis [135] | 3-6,7-5,1-6 | |
| ATP Cordoba | 02/01 19:20 | 64 | [147] Alessandro Giannessi v Facundo D Acosta [496] | 1-6,6-3,2-6 | |
| Challenger Punta del Este | 01/31 22:00 | 27 | [77] Marco Cecchinato v Alessandro Giannessi [147] | 6-3,7-5 | |
| Challenger Punta del Este | 01/30 18:00 | 26 | [147] Alessandro Giannessi v Pedro Sousa [141] | 4-6,6-3,6-4 | |
| Challenger Punta del Este | 01/28 17:45 | 25 | [147] Alessandro Giannessi v Tomas Martin Etcheverry [340] | 5-7,7-5,6-4 | |
| Australian Open | 01/15 02:00 | 44 | [233] Duckhee Lee v Alessandro Giannessi [145] | 2-6,7-5,7-6 | |
| Challenger Hamburg | 10/23 18:00 | 25 | [175] Cedrik-Marcel Stebe v Alessandro Giannessi [149] | 6-2,6-3 | |
| Challenger Santo Domingo | 10/11 23:00 | 27 | [151] Alessandro Giannessi v Hugo Dellien [83] | 3-6,1-6 | |
| Challenger Santo Domingo | 10/10 20:55 | 26 | [112] Guido Andreozzi v Alessandro Giannessi [151] | Retired | |
| Challenger Santo Domingo | 10/09 19:20 | 25 | [352] Thiago Seyboth Wild v Alessandro Giannessi [151] | 1-6,4-6 | |
| Challenger Barcelona | 10/05 09:00 | 28 | [208] Jozef Kovalik v Alessandro Giannessi [166] | 6-3,7-6 | |
| Challenger Barcelona | 10/04 10:30 | 27 | [166] Alessandro Giannessi v Filippo Baldi [158] | 5-7,6-0,6-1 | |
| Challenger Barcelona | 10/03 10:30 | 26 | [177] Filip Horansky v Alessandro Giannessi [166] | 6-7,7-6,4-6 | |
| Challenger Barcelona | 10/02 09:00 | 25 | [328] Ivan Nedelko v Alessandro Giannessi [166] | 1-6,4-6 | |
| Challenger Florence | 09/26 14:05 | 26 | [80] Philipp Kohlschreiber v Alessandro Giannessi [168] | 4-6,6-4,6-3 | |
| Challenger Florence | 09/25 13:55 | 25 | [381] Jules Okala v Alessandro Giannessi [168] | 3-6,0-6 | |
| Challenger Biella | 09/20 12:50 | 27 | [108] Alejandro Davidovich Fokina v Alessandro Giannessi [171] | 6-2,6-1 |
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.