| French Open Qual | 05/21 15:20 | 44 | [112] Gerald Melzer v Alessandro Giannessi [198] | 6-7,2-6 | |
| Challenger Heilbronn | 05/15 11:35 | 25 | [142] Henri Laaksonen v Alessandro Giannessi [192] | 4-6,6-4,6-4 | |
| Challenger Rome | 05/09 08:45 | 26 | [197] Alessandro Giannessi v Adam Pavlasek [245] | 4-6,1-6 | |
| Challenger Rome | 05/08 08:30 | 25 | [262] Matteo Viola v Alessandro Giannessi [197] | 2-6,4-6 | |
| ATP Estoril Qual | 04/28 11:00 | 44 | [190] Joao Domingues v Alessandro Giannessi [162] | 7-5,6-1 | |
| ATP Barcelona Qual | 04/21 08:00 | 45 | [107] Bjorn Fratangelo v Alessandro Giannessi [164] | 7-5,6-4 | |
| Challenger Barletta | 04/11 13:00 | 26 | [237] Marco Trungelliti v Alessandro Giannessi [158] | Retired | |
| Challenger Barletta | 04/10 09:40 | 25 | [483] Zsombor Piros v Alessandro Giannessi [158] | 2-6,1-6 | |
| Challenger Barletta | 04/10 08:00 | - | Lorenzo Sonego v Alessandro Giannessi | Cancelled | |
| Challenger Alicante | 04/04 11:30 | 26 | Mario Vilella Martinez v Alessandro Giannessi | Retired | |
| Challenger Alicante | 04/03 08:00 | 25 | [302] Ivan Gakhov v Alessandro Giannessi [161] | 1-6,6-7 | |
| Challenger Marbella | 03/27 12:25 | 25 | [136] Ramkumar Ramanathan v Alessandro Giannessi [161] | 6-4,3-6,6-3 | |
| Challenger Santiago | 03/06 14:00 | 25 | Jozef Kovalik v Alessandro Giannessi | 6-3,2-6,6-2 | |
| Challenger Punta del Este | 03/02 21:00 | 28 | Simone Bolelli v Alessandro Giannessi | 6-2,7-5 | |
| Challenger Punta del Este | 03/01 18:30 | 27 | Jozef Kovalik v Alessandro Giannessi | 6-7,6-2,6-7 | |
| Challenger Punta del Este | 02/28 18:30 | 26 | Juan Ignacio Galarza v Alessandro Giannessi | 0-6,4-6 | |
| Challenger Punta del Este | 02/26 17:00 | 25 | Hugo Dellien v Alessandro Giannessi | 6-7,6-4,4-6 | |
| ATP Rio De Janeiro Qual | 02/18 19:00 | - | Roberto Carballes Baena v Alessandro Giannessi | 6-3,6-2 | |
| ATP Rio De Janeiro Qual | 02/17 18:00 | 26 | Guilherme Clezar v Alessandro Giannessi | 7-6,4-6,3-6 | |
| ATP Buenos Aires Qual | 02/10 19:40 | 26 | Hernan Casanova v Alessandro Giannessi | 7-6,6-4 | |
| ATP Quito | 02/08 19:30 | 26 | Thiago Monteiro v Alessandro Giannessi | 7-6,4-6,7-5 | |
| ATP Quito | 02/07 17:00 | 25 | Alessandro Giannessi v Peter Polansky | 6-3,6-4 | |
| ATP Quito Qual | 02/04 18:35 | - | Alessandro Giannessi v Federico Gaio | 6-3,6-7,6-7 | |
| ATP Quito Qual | 02/03 18:10 | 26 | Alessandro Giannessi v Juan Ignacio Londero | 6-4,6-4 | |
| Australian Open Qual | 01/12 04:35 | 45 | Ernesto Escobedo v Alessandro Giannessi | 6-3,6-2 | |
| Australian Open Qual | 01/10 08:20 | 44 | Alessandro Giannessi v Sumit Nagal | 7-6,3-6,6-3 | |
| Challenger Bratislava | 11/06 19:20 | 25 | [79] Mikhail Kukushkin v Alessandro Giannessi [139] | 6-0,6-2 | |
| Challenger Brest | 10/26 11:40 | 26 | Alessandro Giannessi v Jeremy Chardy | 1-6,1-6 | |
| Challenger Brest | 10/25 10:35 | 25 | Alexey Vatutin v Alessandro Giannessi | 6-4,2-6,1-6 | |
| ATP Stockholm | 10/17 10:00 | 25 | [84] Jeremy Chardy v Alessandro Giannessi [139] | 6-0,7-5 |
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.