| 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 | |
| ATP Beijing Qual | 09/30 07:00 | 45 | [131] Alessandro Giannessi v Dusan Lajovic [84] | 3-6,6-3,3-6 | |
| ATP Shenzhen | 09/25 06:00 | 25 | [132] Alessandro Giannessi v Jeremy Chardy [83] | 6-7,4-6 | |
| ATP - Metz | 09/18 13:55 | 25 | [132] Alessandro Giannessi v Marius Copil [86] | 3-6,2-6 | |
| Challenger - Stettin | 09/12 10:30 | 25 | [493] Artem Smirnov v Alessandro Giannessi [93] | 7-6,6-1 | |
| Challenger - Genua | 09/07 12:25 | 26 | [123] Guillermo Garcia-Lopez v Alessandro Giannessi [91] | 6-4,7-5 | |
| Challenger - Genua | 09/06 08:30 | 25 | [264] Julian Ocleppo v Alessandro Giannessi [91] | 5-7,1-6 | |
| US Open | 08/28 16:55 | 23 | [91] Alessandro Giannessi v Ernests Gulbis [255] | 4-6,7-6,2-6,5-7 | |
| ATP Kitzbuhel Qual | 07/29 11:30 | 45 | Alessandro Giannessi v Miljan Zekic | 6-3,5-7,4-6 | |
| Challenger Cortina | 07/25 15:30 | 25 | Alessandro Giannessi v Pedro Martinez | 7-5,4-6,4-6 | |
| ATP - Umag | 07/22 18:00 | 28 | [34] Paolo Lorenzi v Alessandro Giannessi [104] | 6-2,4-6,6-3 | |
| ATP - Umag | 07/21 16:00 | 27 | [104] Alessandro Giannessi v Rogerio Dutra Silva [64] | 6-7,6-2,7-5 | |
| ATP - Umag | 07/20 18:45 | 26 | [148] Kenny de Schepper v Alessandro Giannessi [104] | 2-6,6-3,3-6 | |
| ATP - Umag | 07/18 15:00 | 25 | [207] Marc Polmans v Alessandro Giannessi [104] | 7-6,3-6,4-6 | |
| Challenger - Perugia | 07/13 11:40 | 26 | [200] Salvatore Caruso v Alessandro Giannessi [103] | 6-3,6-3 | |
| Challenger - Perugia | 07/12 16:25 | 25 | [155] Stefano Travaglia v Alessandro Giannessi [103] | 3-6,6-4,5-7 | |
| Wimbledon Qual | 06/26 17:10 | 44 | [100] Alessandro Giannessi v Pedro Sousa [153] | 6-4,3-6,4-6 | |
| Challenger - Todi | 06/20 16:15 | 25 | [99] Alessandro Giannessi v Laurynas Grigelis [251] | Retired | |
| Challenger Caltanissetta | 06/18 16:30 | 29 | [36] Paolo Lorenzi v Alessandro Giannessi [118] | 6-4,6-2 | |
| Challenger Caltanissetta | 06/17 15:15 | 28 | [118] Alessandro Giannessi v Cedrik-Marcel Stebe [258] | 6-3,7-6 | |
| Challenger Caltanissetta | 06/16 14:30 | 27 | [118] Alessandro Giannessi v Mikhail Kukushkin [126] | 6-4,1-6,6-1 | |
| Challenger Caltanissetta | 06/15 19:20 | 26 | [118] Alessandro Giannessi v Inigo Cervantes [177] | 6-2,6-3 | |
| Challenger Caltanissetta | 06/13 12:15 | 25 | [118] Alessandro Giannessi v Enrique Lopez-Perez [236] | 7-5,7-5 | |
| Challenger - Vicenza | 05/30 16:25 | 25 | [206] Filip Krajinovic v Alessandro Giannessi [109] | 6-3,3-6,6-3 | |
| French Open Qual | 05/24 15:55 | 45 | [108] Alessandro Giannessi v Matteo Donati [226] | 3-6,6-3,6-7 | |
| French Open Qual | 05/23 08:00 | 44 | [108] Alessandro Giannessi v Calvin Hemery [269] | 7-5,6-3 | |
| ATP Rome Qual | 05/13 11:40 | 45 | [110] Alessandro Giannessi v Ernesto Escobedo [81] | 3-6,4-6 | |
| Challenger - Francavilla | 04/30 13:00 | 29 | [219] Pedro Sousa v Alessandro Giannessi [121] | 6-3,7-6 | |
| Challenger - Francavilla | 04/29 14:50 | 28 | [225] Stefano Travaglia v Alessandro Giannessi [121] | 7-5,4-6,2-6 |
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.