| Challenger Padova | 07/01 12:45 | 26 | Alessandro Giannessi v Riccardo Bellotti | 3-6,6-1,6-4 | |
| Challenger Padova | 06/30 09:30 | 25 | Alessandro Giannessi v Andrey Rublev | 3-6,6-2,6-4 | |
| Challenger Padova Qual | 06/29 10:00 | 44 | Nicolas Barrientos v Alessandro Giannessi | 2-6,2-6 | |
| Challenger - Milan | 06/21 09:00 | 44 | Benoit Paire v Alessandro Giannessi | 6-3,6-3 | |
| ITF Italy F13 | 06/12 15:30 | - | Alessandro Giannessi v Christian Trubrig | 6-4,3-6,7-6 | |
| ITF Italy F13 | 06/11 13:30 | - | Alessandro Giannessi v Claudio Fortuna | 6-2,6-3 | |
| ITF Italy F13 | 06/10 12:30 | - | Alessandro Giannessi v Riccardo Bonadio | 6-3,6-0 | |
| ITF Italy F13 | 06/09 17:00 | - | Gianni Mina v Alessandro Giannessi | 6-7,3-6 | |
| ITF Italy F12 | 06/06 13:00 | - | Alessandro Giannessi v Yann Marti | 6-7,7-5,6-4 | |
| ITF Italy F12 | 06/05 14:30 | - | Johan Sebastien Tatlot v Alessandro Giannessi | 3-6,5-7 | |
| ITF Italy F12 | 06/04 11:00 | - | Riccardo Ghedin v Alessandro Giannessi | 2-6,1-6 | |
| ITF Italy F12 | 06/03 11:40 | - | Alessandro Giannessi v Mateo Nicolas Martinez | 6-4,6-3 | |
| ITF Italy F11 | 05/26 14:50 | - | Alessandro Giannessi v Maxime Tabatruong | 7-5,4-6,5-7 | |
| Challenger - Biella | 09/09 11:25 | 25 | Alessandro Giannessi v Henri Laaksonen | 6-7,6-4,2-6 | |
| Challenger - Genova | 09/02 09:30 | 25 | Alessandro Giannessi v Guido Andreozzi | 5-7,2-6 | |
| Challenger Cortina | 07/30 15:20 | 25 | Alessandro Giannessi v Walter Trusendi | 3-6,6-3,3-6 | |
| ITF Italy F23 | 07/18 14:25 | - | Federico Gaio v Alessandro Giannessi | Retired | |
| ITF Italy F23 | 07/17 13:00 | - | Maximiliano Estevez v Alessandro Giannessi | 6-7,4-6 | |
| ITF Italy F23 | 07/15 14:05 | - | Deni Zmak v Alessandro Giannessi | 6-7,3-6 | |
| Challenger - San Benedetto | 07/10 19:50 | 26 | Andreas Haider-Maurer v Alessandro Giannessi | 6-1,6-3 | |
| Challenger - San Benedetto | 07/08 14:40 | 25 | Alessandro Giannessi v Gerard Granollers-Pujol | 6-1,6-1 | |
| Challenger - Todi | 07/02 08:00 | 25 | Alessandro Giannessi v Maximo Gonzalez | 6-7,2-6 | |
| Challenger Padova | 06/27 11:00 | 27 | Alessandro Giannessi v Jordi Samper-Montana | 4-6,5-7 | |
| Challenger Padova | 06/26 09:30 | 26 | Adrian Ungur v Alessandro Giannessi | 5-7,0-6 | |
| Challenger Milan Qual | 06/16 09:20 | 44 | Alessandro Giannessi v Juan Lizariturry | 4-6,4-6 | |
| Challenger Mestre | 06/05 09:30 | 26 | Alessandro Giannessi v Pablo Cuevas | 0-6,4-6 | |
| Challenger Mestre | 06/04 11:15 | 25 | Salvatore Caruso v Alessandro Giannessi | 6-7,3-6 | |
| Challenger Mestre Qual | 06/02 12:30 | 44 | Alessandro Giannessi v Christian Lindell | 7-6,7-5 | |
| Challenger - Rom | 05/05 14:40 | 25 | Alessandro Giannessi v Norbert Gombos | 6-7,2-6 | |
| ITF Croatia F4 | 03/21 12:10 | - | Juan Lizariturry v Alessandro Giannessi | Retired |
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.