| Challenger Braga | 09/22 09:00 | 26 | [247] Jesper De Jong v Alessandro Giannessi [182] | 6-3,7-5 | |
| Challenger Braga | 09/21 09:00 | 25 | [371] Kaichi Uchida v Alessandro Giannessi [182] | 4-6,1-6 | |
| Challenger Como | 08/30 11:05 | 25 | Riccardo Bonadio v Alessandro Giannessi | Cancelled | |
| US Open | 08/25 20:35 | 14 | [171] Alessandro Giannessi v Hugo Dellien [137] | 1-6,3-6 | |
| Challenger Trieste | 07/29 15:05 | 26 | [169] Alessandro Giannessi v Vitaliy Sachko [271] | 7-6,4-6,0-6 | |
| Challenger Trieste | 07/28 08:00 | 25 | [169] Alessandro Giannessi v Rudolf Molleker [375] | 4-6,6-2,6-1 | |
| ATP Umag | 07/21 14:30 | 26 | [177] Alessandro Giannessi v Richard Gasquet [59] | 6-7,4-6 | |
| ATP Umag | 07/20 14:00 | 25 | [177] Alessandro Giannessi v Jiri Vesely [86] | 7-6,7-5 | |
| ATP Umag | 07/19 14:30 | 19 | [177] Alessandro Giannessi v Renzo Olivo [215] | 7-6,6-1 | |
| ATP Umag | 07/18 14:00 | 14 | [168] Alessandro Giannessi v Rudolf Molleker [314] | 6-3,7-5 | |
| ATP Hamburg | 07/11 10:30 | 19 | [200] Maximilian Marterer v Alessandro Giannessi [163] | 3-6,6-3,7-5 | |
| ATP Hamburg | 07/10 12:05 | 14 | [235] Tobias Kamke v Alessandro Giannessi [163] | 3-6,4-6 | |
| Wimbledon | 06/22 10:00 | 14 | [122] Bernabe Zapata Miralles v Alessandro Giannessi [162] | 7-6,6-3 | |
| Challenger Forli | 06/15 16:05 | 25 | [467] Jacopo Berrettini v Alessandro Giannessi [162] | 6-1,7-6 | |
| Challenger Lyon | 06/07 09:40 | 25 | Bjorn Fratangelo v Alessandro Giannessi | Cancelled | |
| French Open | 05/30 12:30 | 23 | [49] Kei Nishikori v Alessandro Giannessi [159] | 6-4,6-7,6-3,4-6,6-4 | |
| French Open | 05/28 11:05 | 19 | [116] Francisco Cerundolo v Alessandro Giannessi [159] | 4-6,6-3,2-6 | |
| French Open | 05/26 13:10 | 15 | [159] Alessandro Giannessi v Tallon Griekspoor [131] | 7-5,7-5 | |
| French Open | 05/25 11:25 | 14 | [200] Ruben Bemelmans v Alessandro Giannessi [159] | 4-6,7-6,5-7 | |
| ATP Lyon | 05/17 08:00 | 19 | [160] Alessandro Giannessi v Kamil Majchrzak [129] | 4-6,3-6 | |
| ATP Lyon | 05/16 09:40 | 14 | [244] Peter Polansky v Alessandro Giannessi [161] | 3-6,4-6 | |
| ATP Lyon | 05/16 09:20 | 14 | Lorenzo Musetti v Alessandro Giannessi | Cancelled | |
| Challenger Heilbronn | 05/12 13:15 | 26 | [161] Alessandro Giannessi v Daniel Elahi Galan [110] | 7-6,6-7,4-6 | |
| Challenger Heilbronn | 05/10 15:40 | 25 | [161] Alessandro Giannessi v Prajnesh Gunneswaran [148] | 7-6,6-1 | |
| Challenger Biella | 05/04 08:00 | 25 | [159] Alessandro Giannessi v Juan P Varillas [150] | 4-6,5-7 | |
| Challenger Rome | 05/01 12:45 | 28 | [167] Alessandro Giannessi v Juan Manuel Cerundolo [176] | 6-4,4-6,5-7 | |
| Challenger Rome | 04/30 11:20 | 27 | [167] Alessandro Giannessi v Thanasi Kokkinakis [209] | 7-5,3-6,7-5 | |
| Challenger Rome | 04/28 11:20 | 26 | [167] Alessandro Giannessi v Jay Clarke [236] | 6-2,6-4 | |
| Challenger Rome | 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 |
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.