| Challenger - Lissabon | 10/16 12:30 | 27 | [298] Dimitar Kuzmanov v Alessandro Giannessi [164] | 4-6,3-6 | |
| Challenger - Lissabon | 10/14 10:55 | 26 | [164] Alessandro Giannessi v Paolo Lorenzi [134] | 7-5,6-3 | |
| Challenger - Lissabon | 10/12 09:00 | 25 | [172] Alessandro Giannessi v Roberto Cid Subervi [214] | 6-3,5-7,6-2 | |
| 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 - Rom | 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 - Hamborg | 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 |
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.