| Challenger Biella | 02/12 12:40 | 27 | [212] Illya Marchenko v Lorenzo Giustino [157] | 6-2,2-6,7-5 | |
| Challenger Biella | 02/11 10:30 | 26 | [182] Roberto Marcora v Lorenzo Giustino [157] | 6-7,5-7 | |
| Challenger Biella | 02/09 16:25 | 25 | [337] Jelle Sels v Lorenzo Giustino [157] | 4-6,3-6 | |
| Challenger Antalya | 02/01 13:50 | 25 | [118] Thiago Seyboth Wild v Lorenzo Giustino [154] | 6-4,6-3 | |
| Challenger Antalya | 01/28 08:40 | 25 | [224] Zdenek Kolar v Lorenzo Giustino [154] | 6-3,3-6,7-5 | |
| Challenger Istanbul | 01/21 07:00 | 26 | [151] Lorenzo Giustino v Antoine Hoang [121] | 4-6,4-6 | |
| Challenger Istanbul | 01/18 11:25 | 25 | [151] Lorenzo Giustino v Alessandro Giannessi [162] | 7-5,7-6 | |
| Ausztrál Open | 01/12 07:30 | 15 | [223] Borna Gojo v Lorenzo Giustino [151] | 6-3,7-6 | |
| Ausztrál Open | 01/10 07:30 | 60 | [183] Denis Istomin v Lorenzo Giustino [151] | 1-6,1-6 | |
| Challenger Maia | 11/30 12:45 | 25 | [374] Duje Ajdukovic v Lorenzo Giustino [149] | 7-5,6-2 | |
| Challenger Bratislava | 11/12 13:10 | 26 | [316] Lukas Klein v Lorenzo Giustino [147] | 6-4,6-3 | |
| Challenger Bratislava | 11/10 09:00 | 25 | [169] Yannick Maden v Lorenzo Giustino [147] | 5-7,6-3,4-6 | |
| Challenger Marbella | 10/29 15:15 | 26 | [146] Lorenzo Giustino v Jaume Munar [108] | 1-6,3-6 | |
| Challenger Marbella | 10/27 11:30 | 25 | [136] Carlos Alcaraz v Lorenzo Giustino [145] | 6-3,5-7,4-6 | |
| Challenger Istanbul | 10/19 08:30 | 25 | [336] Altug Celikbilek v Lorenzo Giustino [140] | 6-0,6-3 | |
| Challenger Alicante | 10/12 12:15 | 25 | [203] Liam Broady v Lorenzo Giustino [140] | 7-5,6-3 | |
| Challenger Barcelona | 10/08 12:55 | 26 | [157] Lorenzo Giustino v Filip Horansky [177] | 3-6,6-3,2-6 | |
| Challenger Barcelona | 10/06 11:30 | 25 | [223] Francisco Cerundolo v Lorenzo Giustino [157] | 1-6,4-6 | |
| French Open | 09/30 11:45 | 24 | [157] Lorenzo Giustino v Diego Schwartzman [14] | 1-6,5-7,0-6 | |
| French Open | 09/27 17:10 | 23 | [70] Corentin Moutet v Lorenzo Giustino [156] | 6-0,6-7,6-7,6-2,16-18 | |
| French Open | 09/24 11:00 | 19 | [246] Dustin Brown v Lorenzo Giustino [156] | 3-6,5-7 | |
| French Open | 09/23 13:05 | 15 | [156] Lorenzo Giustino v Hugo Grenier [249] | 3-6,6-4,7-5 | |
| French Open | 09/21 08:00 | 14 | [155] Lorenzo Giustino v Maximilian Marterer [263] | 6-3,5-7,7-6 | |
| Challenger Prostejov | 09/09 11:10 | 26 | [56] Pablo Andujar v Lorenzo Giustino [154] | Retired | |
| Challenger Prostejov | 09/07 11:10 | 25 | [148] Daniel Elahi Galan v Lorenzo Giustino [154] | 6-2,3-6,4-6 | |
| Challenger Cordenons | 09/02 12:00 | 25 | [170] Mario Vilella Martinez v Lorenzo Giustino [154] | 6-4,2-6,6-4 | |
| Challenger Trieste | 08/24 14:00 | - | [152] Lorenzo Giustino v Matteo Viola [222] | 4-6,2-6 | |
| Challenger Todi | 08/17 12:30 | - | [153] Lorenzo Giustino v Daniel Altmaier [219] | 6-3,3-6,2-6 | |
| Spanyol Summer League | 07/17 12:20 | - | [153] Lorenzo Giustino v Javier Barranco Cosano [296] | 6-7,1-6 | |
| Spanyol Summer League | 07/16 15:00 | - | [153] Lorenzo Giustino v Eduard Esteve Lobato [465] | Retired |
Lorenzo Giustino (Italian pronunciation: [loˈrɛntso dʒuˈstiːno]; born 10 September 1991, in Naples) is an Italian tennis player.
Giustino has a career-high ATP singles ranking of 127 achieved on 12 August 2019 and a career-high ATP doubles ranking of 311 achieved on 15 April 2019.
Giustino made his ATP main draw debut at the 2015 BRD Năstase Țiriac Trophy, where he qualified for the main draw.
Giustino made his Grand Slam debut at the 2020 Australian Open. He defeated Frenchman Corentin Moutet 0–6, 7–6 (7), 7–6 (3), 2–6, 18–16 in the first round of 2020 French Open as a first time main draw qualifier at this Major. The match was the second-longest in French Open history, lasting 6 hours, 5 minutes. It was his first ATP tour-level win.
He qualified for his first ATP 500 tournament at the 2021 Dubai Tennis Championships as a lucky loser receiving a bye into the second round after the withdrawal of tenth seed Borna Ćorić.
He qualified for his second ATP 500 at the 2023 Barcelona Open Banc Sabadell.