| Challenger - San Marino | 08/08 15:00 | 25 | [175] Nino Serdarusic v Lorenzo Giustino [253] | 6-7,6-4,3-6 | |
| Challenger - Liberec | 08/02 11:35 | 25 | Lorenzo Giustino v Sumit Nagal | 3-6,6-2,6-7 | |
| Challenger Zug | 07/29 11:00 | 27 | [189] Dimitar Kuzmanov v Lorenzo Giustino [260] | 6-4,6-4 | |
| Challenger Zug | 07/27 09:00 | 26 | [260] Lorenzo Giustino v Jan-Lennard Struff [121] | 6-4,7-6 | |
| Challenger Zug | 07/26 11:55 | 25 | [260] Lorenzo Giustino v Maximilian Neuchrist [377] | 6-2,4-6,7-5 | |
| Challenger Zug | 07/25 10:00 | 19 | [260] Lorenzo Giustino v Edoardo Lavagno [395] | 6-2,6-4 | |
| Challenger Zug | 07/24 10:20 | 14 | Lorenzo Giustino v Mirko Martinez | 6-3,6-3 | |
| Challenger - Tampere | 07/21 13:50 | 26 | [110] Juan Manuel Cerundolo v Lorenzo Giustino [261] | 7-6,6-1 | |
| Challenger - Tampere | 07/19 16:05 | 25 | [270] Patrik Niklas-Salminen v Lorenzo Giustino [261] | 2-6,3-6 | |
| Challenger - Verona | 07/10 11:50 | 14 | Lorenzo Giustino v Remy Bertola | 2-6,3-6 | |
| Challenger Braunschweig | 07/03 09:00 | 14 | [275] Lorenzo Giustino v Oscar Jose Gutierrez [389] | 4-6,2-6 | |
| Challenger - Troyes | 06/29 10:10 | 26 | [291] Juan Bautista Torres v Lorenzo Giustino [275] | 6-4,6-3 | |
| Challenger - Troyes | 06/27 17:25 | 25 | [275] Lorenzo Giustino v Genaro A Olivieri [224] | 7-5,6-7,6-1 | |
| Wimbledon | 06/20 10:00 | 14 | [273] Lorenzo Giustino v Mikhail Kukushkin [160] | 2-6,1-6 | |
| Challenger - Blois | 06/13 13:25 | 25 | [263] Lorenzo Giustino v Vit Kopriva [139] | 6-2,4-6,6-7 | |
| Challenger - Poznań | 05/31 08:00 | 25 | [68] Arthur Rinderknech v Lorenzo Giustino [207] | 6-4,6-0 | |
| Challenger - Vicenza | 05/23 17:30 | 25 | [222] Andrea Pellegrino v Lorenzo Giustino [207] | 6-4,6-4 | |
| French Open | 05/18 08:00 | 15 | [287] Pedro Sousa v Lorenzo Giustino [205] | 6-4,6-1 | |
| French Open | 05/16 11:40 | 14 | [205] Lorenzo Giustino v Dennis Novak [150] | 7-5,7-6 | |
| Challenger - Praag | 05/08 10:20 | 29 | [176] Pedro Cachin v Lorenzo Giustino [223] | 6-3,7-6 | |
| Challenger - Praag | 05/07 09:00 | 28 | [223] Lorenzo Giustino v Dimitar Kuzmanov [206] | 7-6,4-6,6-2 | |
| Challenger - Praag | 05/06 09:00 | 27 | [183] Federico Gaio v Lorenzo Giustino [223] | 3-6,6-3,6-7 | |
| Challenger - Praag | 05/04 10:35 | 26 | Lorenzo Giustino v Matteo Donati | 6-1,6-3 | |
| Challenger - Praag | 05/02 14:15 | 25 | [237] Marius Copil v Lorenzo Giustino [223] | 6-3,6-7,5-7 | |
| Challenger - Ostrava | 04/27 11:25 | 26 | [380] Mats Rosenkranz v Lorenzo Giustino [224] | 6-1,5-7,6-4 | |
| Challenger - Ostrava | 04/26 09:45 | 25 | [224] Lorenzo Giustino v Gregoire Barrere [228] | 6-4,5-7,6-4 | |
| Challenger - Praag | 04/22 12:20 | 27 | [246] Dalibor Svrcina v Lorenzo Giustino [222] | Retired | |
| Challenger - Praag | 04/21 12:15 | 26 | [222] Lorenzo Giustino v Emilio Nava [365] | 5-7,7-6,7-6 | |
| Challenger - Praag | 04/20 08:30 | 25 | [222] Lorenzo Giustino v Ryan Peniston [224] | 6-2,6-3 | |
| Challenger - Barletta | 04/12 11:50 | 25 | [179] Enzo Couacaud v Lorenzo Giustino [216] | 6-4,6-4 |
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.