| Challenger - Rom | 04/26 13:15 | 25 | [160] Alessandro Giannessi v Denis Yevseyev [345] | Retired | |
| Challenger - Madrid | 04/12 14:30 | 25 | [164] Alessandro Giannessi v Marco Trungelliti [194] | 2-6,6-2,3-6 | |
| 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 |
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.