| Challenger - Gran Canaria | 02/23 10:00 | 25 | [158] Lorenzo Giustino v Roberto Ortega-Olmedo [297] | 6-1,3-6,4-6 | |
| 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] Zdeněk Kolář 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 | |
| Australian Open | 01/12 07:30 | 15 | [223] Borna Gojo v Lorenzo Giustino [151] | 6-3,7-6 | |
| Australian 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] Lukáš 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 - Prostějov | 09/09 11:10 | 26 | [56] Pablo Andujar v Lorenzo Giustino [154] | Retired | |
| Challenger - Prostějov | 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 | |
| Španielsko - Summer League | 07/17 12:20 | - | [153] Lorenzo Giustino v Javier Barranco Cosano [296] | 6-7,1-6 |
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.