| Open d'Australie | 01/15 23:00 | 44 | [149] Lorenzo Giustino v Yan Bai [218] | 6-3,7-5 | |
| Challenger Canberra | 01/06 06:35 | 24 | [162] Oscar Otte v Lorenzo Giustino [149] | 5-7,6-1,6-4 | |
| Challenger Lima | 10/23 17:25 | 25 | [226] Matos, Rafael v Lorenzo Giustino [147] | Retired | |
| Challenger - Barcelone | 10/02 15:00 | 25 | [227] Carlos Taberner v Lorenzo Giustino [142] | 6-4,6-0 | |
| Florence, Italy | 09/25 13:20 | 25 | [244] Mohamed Safwat v Lorenzo Giustino [144] | 6-3,2-6,6-3 | |
| Challenger Biella | 09/17 14:30 | 25 | [219] Andrea Collarini v Lorenzo Giustino [141] | 7-6,5-7,6-3 | |
| Challenger Szczecin | 09/11 08:00 | 25 | [138] Lorenzo Giustino v Jozef Kovalik [346] | 7-6,6-7,1-6 | |
| Genoa, Italy | 09/03 10:00 | 25 | [128] Lorenzo Giustino v Giulio Zeppieri [470] | 3-6,2-6 | |
| Challenger Como | 08/27 12:00 | 25 | [128] Lorenzo Giustino v Facundo Mena [266] | 3-6,2-6 | |
| US Open, New York, USA | 08/20 15:00 | 44 | [166] Garcia-Lopez, Guillermo v Lorenzo Giustino [128] | 3-6,7-5,6-2 | |
| Challenger Manerbio | 08/09 13:00 | 27 | [177] Federico Gaio v Lorenzo Giustino [130] | Retired | |
| Challenger Manerbio | 08/09 08:00 | 26 | [267] Pavel Kotov v Lorenzo Giustino [130] | 6-1,4-6,5-7 | |
| Challenger Manerbio | 08/07 10:50 | 25 | [400] Cuevas, Martin v Lorenzo Giustino [130] | 6-7,6-3,3-6 | |
| Sopot, Pologne | 07/30 11:00 | 25 | [131] Lorenzo Giustino v Aslan Karatsev [321] | 6-7,3-6 | |
| Challenger - Prague | 07/26 13:30 | 27 | [266] Vilella Martinez, Mario v Lorenzo Giustino [137] | 6-0,7-6 | |
| Challenger - Prague | 07/25 08:00 | 26 | [364] Safranek, Vaclav v Lorenzo Giustino [137] | 3-6,2-6 | |
| Challenger - Prague | 07/23 09:35 | 25 | [308] Wang, Tak Khunn v Lorenzo Giustino [137] | 3-6,2-6 | |
| Nur Sultan, Kazakhstan | 07/16 12:00 | 25 | [382] Sebastian Korda v Lorenzo Giustino [130] | 7-5,6-3 | |
| Challenger Recanati | 07/03 17:30 | 25 | [132] Lorenzo Giustino v Bega, Alessandro [361] | 6-7,2-6 | |
| Wimbledon, London, Great Britain | 06/24 14:40 | 44 | [198] Daniel Elahi Galan v Lorenzo Giustino [134] | 7-6,6-3 | |
| Challenger Blois | 06/22 12:00 | 28 | [122] Sousa, Pedro v Lorenzo Giustino [141] | 6-4,6-2 | |
| Challenger Blois | 06/21 14:30 | 27 | [141] Lorenzo Giustino v Daniel Elahi Galan [197] | 6-3,6-1 | |
| Challenger Blois | 06/20 17:30 | 26 | [141] Lorenzo Giustino v Steven Diez [239] | 7-6,3-6,7-6 | |
| Challenger Blois | 06/19 11:05 | 25 | [141] Lorenzo Giustino v Alexandre Muller [297] | 3-6,6-4,6-4 | |
| Shymkent II, Kazakhstan | 06/14 06:30 | 27 | [201] Federico Coria v Lorenzo Giustino [144] | 6-7,6-3,6-1 | |
| Shymkent II, Kazakhstan | 06/13 08:40 | 26 | [245] Kaichi Uchida v Lorenzo Giustino [144] | 3-6,2-6 | |
| Shymkent II, Kazakhstan | 06/12 06:00 | 25 | [340] Crepatte, Baptiste v Lorenzo Giustino [144] | 2-6,2-6 | |
| Challenger Almaty | 06/09 05:00 | 29 | [159] Lorenzo Giustino v Federico Coria [234] | 6-4,6-4 | |
| Challenger Almaty | 06/08 06:20 | 28 | [159] Lorenzo Giustino v Vilella Martinez, Mario [292] | 7-5,4-6,6-2 | |
| Challenger Almaty | 06/07 06:55 | 27 | [353] Alejandro Tabilo v Lorenzo Giustino [159] | 3-6,6-1,3-6 |
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.