| Challenger - Rooma | 05/01 12:45 | 28 | [167] Alessandro Giannessi v Juan Manuel Cerundolo [176] | 6-4,4-6,5-7 | |
| Challenger - Rooma | 04/30 11:20 | 27 | [167] Alessandro Giannessi v Thanasi Kokkinakis [209] | 7-5,3-6,7-5 | |
| Challenger - Rooma | 04/28 11:20 | 26 | [167] Alessandro Giannessi v Jay Clarke [236] | 6-2,6-4 | |
| Challenger - Rooma | 04/26 11:05 | 25 | [167] Alessandro Giannessi v Guido Andreozzi [217] | 6-3,6-3 | |
| Challenger – Belgrade | 04/14 08:45 | 25 | [147] Blaz Rola v Alessandro Giannessi [166] | Retired | |
| Challenger – Belgrade | 04/12 11:20 | 19 | [166] Alessandro Giannessi v Maxime Janvier [222] | 3-6,6-4,6-4 | |
| Challenger – Belgrade | 04/11 13:05 | 14 | Alessandro Giannessi v Marko Topo | 2-6,7-6,6-2 | |
| ATP Marbella | 04/04 13:35 | 14 | [169] Alessandro Giannessi v Nikola Milojevic [148] | Retired | |
| Challenger – Marbella | 04/03 10:00 | 28 | [169] Alessandro Giannessi v Gianluca Mager [102] | 7-6,4-6,1-6 | |
| Challenger – Marbella | 04/02 12:00 | 27 | [161] Martin Klizan v Alessandro Giannessi [169] | 0-6,3-6 | |
| Challenger – Marbella | 03/31 11:50 | 26 | [169] Alessandro Giannessi v Pedro Sousa [111] | 6-4,6-3 | |
| Challenger – Marbella | 03/29 12:00 | 25 | [188] Joao Domingues v Alessandro Giannessi [169] | 3-6,4-6 | |
| Challenger Zadar | 03/24 09:00 | 26 | [169] Alessandro Giannessi v Nerman Fatic [381] | 6-7,7-5,6-7 | |
| Challenger Zadar | 03/22 14:35 | 25 | [169] Alessandro Giannessi v Riccardo Bonadio [289] | 7-5,7-5 | |
| Challenger Gran Canaria | 03/05 16:05 | 27 | [163] Alessandro Giannessi v Carlos Gimeno Valero [400] | 2-6,6-4,2-6 | |
| Challenger Gran Canaria | 03/03 13:00 | 26 | [163] Alessandro Giannessi v Nikolas S Izquierdo [363] | 7-6,7-5 | |
| Challenger Gran Canaria | 03/02 13:05 | 25 | Alessandro Giannessi v Emilio Nava | 6-2,6-3 | |
| Challenger Gran Canaria | 02/24 12:00 | 26 | [190] Steven Diez v Alessandro Giannessi [163] | 7-6,7-6 | |
| Challenger Gran Canaria | 02/23 11:00 | 25 | [283] Stefano Napolitano v Alessandro Giannessi [163] | 0-6,2-6 | |
| Challenger Biella | 02/16 14:10 | 25 | [160] Alessandro Giannessi v Thomas Fabbiano [174] | 1-6,4-6 | |
| Challenger Antalya | 02/06 09:35 | 28 | [165] Alessandro Giannessi v Jaume Munar [103] | Retired | |
| Challenger Antalya | 02/05 08:00 | 27 | [165] Alessandro Giannessi v Alejandro Tabilo [170] | 5-7,7-5,6-1 | |
| Challenger Antalya | 02/03 08:00 | 26 | [165] Alessandro Giannessi v Mohamed Safwat [147] | 6-3,6-4 | |
| Challenger Antalya | 02/02 07:30 | 25 | [132] Daniel Altmaier v Alessandro Giannessi [165] | 6-7,2-6 | |
| Challenger Antalya | 01/30 07:00 | 27 | [110] Jaume Munar v Alessandro Giannessi [165] | 3-6,6-2,6-0 | |
| Challenger Antalya | 01/29 11:00 | 26 | [228] Roberto Cid Subervi v Alessandro Giannessi [165] | 3-6,2-6 | |
| Challenger Antalya | 01/28 10:10 | 25 | [165] Alessandro Giannessi v Jozef Kovalik [125] | 6-4,7-5 | |
| Challenger - Istanbul | 01/18 11:25 | 25 | [151] Lorenzo Giustino v Alessandro Giannessi [162] | 7-5,7-6 | |
| Austraalia lahtised meistrivõistlused | 01/10 10:40 | 60 | [162] Alessandro Giannessi v Mario Vilella Martinez [186] | 1-6,3-6 | |
| ATP Pariis | 10/31 10:25 | 14 | [163] Alessandro Giannessi v Radu Albot [85] | 5-7,4-6 |
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.