| Challenger Oeiras | 04/10 12:25 | 29 | [178] Alessandro Giannessi v Gastao Elias [173] | 6-7,1-6 | |
| Challenger Oeiras | 04/09 09:00 | 28 | [181] Jozef Kovalik v Alessandro Giannessi [178] | 6-2,4-6,5-7 | |
| Challenger Oeiras | 04/08 11:20 | 27 | [153] Christopher O'Connell v Alessandro Giannessi [178] | 4-6,4-6 | |
| Challenger Oeiras | 04/07 11:10 | 26 | [337] Fabian Marozsan v Alessandro Giannessi [178] | 7-5,6-7,4-6 | |
| Challenger Oeiras | 04/05 15:50 | 25 | [298] Luciano Darderi v Alessandro Giannessi [178] | 6-4,6-7,1-6 | |
| Challenger Oeiras | 04/02 09:00 | 28 | [174] Alessandro Giannessi v Gastao Elias [198] | 3-6,3-6 | |
| Challenger Oeiras | 04/01 10:30 | 27 | [174] Alessandro Giannessi v Giulio Zeppieri [239] | 1-6,7-5,6-3 | |
| Challenger Oeiras | 03/30 11:20 | 26 | [174] Alessandro Giannessi v Riccardo Bonadio [256] | 6-2,6-1 | |
| Challenger Oeiras | 03/28 16:10 | 25 | [174] Alessandro Giannessi v Nicola Kuhn [246] | 6-3,6-4 | |
| Challenger Roseto | 03/19 10:00 | 28 | [199] Manuel Guinard v Alessandro Giannessi [186] | 7-5,6-1 | |
| Challenger Roseto | 03/18 12:15 | 27 | [240] Zsombor Piros v Alessandro Giannessi [186] | 2-6,5-7 | |
| Challenger Roseto | 03/17 10:00 | 26 | [186] Alessandro Giannessi v Andrea Pellegrino [201] | 6-4,6-2 | |
| Challenger Roseto | 03/15 12:45 | 25 | [186] Alessandro Giannessi v Nicolas Alvarez Varona [304] | 3-6,6-1,6-3 | |
| Challenger Roseto | 03/10 10:00 | 26 | [288] Lukas Rosol v Alessandro Giannessi [186] | 6-3,6-4 | |
| Challenger Roseto | 03/08 12:15 | 25 | [186] Alessandro Giannessi v Andrej Martin [127] | 6-0,2-6,6-4 | |
| Challenger Gran Canaria | 02/28 16:40 | 25 | [184] Alessandro Giannessi v Lukas Rosol [297] | 6-7,6-3,6-7 | |
| ATP Santiago | 02/19 15:00 | 14 | [224] Felipe Meligeni Rodrigues Alves v Alessandro Giannessi [197] | 6-2,6-4 | |
| ATP Buenos Aires | 02/05 16:00 | 14 | [109] Hugo Dellien v Alessandro Giannessi [184] | 7-6,6-1 | |
| ATP Cordoba | 01/29 15:00 | 25 | [129] Juan Pablo Varillas v Alessandro Giannessi [184] | 7-6,6-2 | |
| Australian Open | 01/14 05:30 | 19 | [126] Yannick Hanfmann v Alessandro Giannessi [184] | 7-6,7-6 | |
| Australian Open | 01/12 05:10 | 15 | [184] Alessandro Giannessi v Quentin Halys [153] | 3-6,6-3,7-6 | |
| Australian Open | 01/11 02:30 | 14 | [183] Marc-Andrea Huesler v Alessandro Giannessi [184] | 4-6,6-3,3-6 | |
| Challenger Pau | 11/16 14:50 | 25 | [188] Alessandro Giannessi v Georgii Kravchenko [397] | 5-7,6-4,2-6 | |
| Challenger Ortisei | 11/09 10:25 | 25 | [191] Alessandro Giannessi v Nerman Fatic [317] | 7-6,3-6,5-7 | |
| Challenger Losinj | 10/23 14:35 | 28 | [204] Alessandro Giannessi v Carlos Taberner [111] | 4-6,3-6 | |
| Challenger Losinj | 10/23 10:35 | 27 | [204] Alessandro Giannessi v Raul Brancaccio [319] | 6-3,6-7,6-1 | |
| Challenger Losinj | 10/20 12:00 | 26 | [204] Alessandro Giannessi v Franco Agamenone [210] | 7-6,3-6,6-1 | |
| Challenger Losinj | 10/19 08:00 | 25 | [204] Alessandro Giannessi v Robin Haase [229] | 7-6,7-5 | |
| Challenger Napoli | 10/05 11:00 | 25 | [439] Matteo Arnaldi v Alessandro Giannessi [185] | Retired | |
| Challenger Lisbon | 09/27 15:00 | 25 | Giulio Zeppieri v Alessandro Giannessi | Cancelled |
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.