| Challenger Todi | 07/13 11:00 | 25 | [472] Giovanni Fonio v Lorenzo Giustino [227] | 6-4,6-3 | |
| Challenger Perugia | 07/06 11:10 | 25 | [325] Timofey Skatov v Lorenzo Giustino [228] | 1-6,7-6,6-0 | |
| Challenger Porto | 06/29 11:25 | 25 | [228] Lorenzo Giustino v Frederico Ferreira Silva [176] | 4-6,6-4,3-6 | |
| Wimbledon | 06/22 11:35 | 14 | [215] Lorenzo Giustino v Illya Marchenko [155] | 5-7,6-7 | |
| Challenger Almaty | 06/15 09:10 | 25 | [215] Lorenzo Giustino v Pavel Kotov [270] | 6-7,4-6 | |
| Challenger Almaty | 06/07 05:35 | 25 | [178] Lorenzo Giustino v Timofey Skatov [399] | 4-6,6-3,2-6 | |
| Challenger Biella | 06/03 11:30 | 26 | [237] Marco Trungelliti v Lorenzo Giustino [178] | 6-4,6-2 | |
| Challenger Biella | 06/01 13:30 | 25 | Luca Nardi v Lorenzo Giustino | Retired | |
| French Open | 05/25 14:25 | 14 | [178] Lorenzo Giustino v Zhizhen Zhang [175] | 7-5,5-7,2-6 | |
| ATP Geneva | 05/16 13:10 | 19 | [104] Pablo Cuevas v Lorenzo Giustino [174] | 6-2,6-4 | |
| ATP Geneva | 05/15 11:00 | 14 | [174] Lorenzo Giustino v Peter Gojowczyk [132] | 6-2,6-3 | |
| Challenger Biella | 05/04 08:00 | 25 | [242] Dimitar Kuzmanov v Lorenzo Giustino [175] | 6-3,1-6,6-3 | |
| Challenger Biella | 05/04 08:00 | 25 | [208] Aleksandar Vukic v Lorenzo Giustino [175] | Cancelled | |
| Challenger Rome | 04/29 14:40 | 26 | [210] Cem Ilkel v Lorenzo Giustino [174] | 6-4,6-2 | |
| Challenger Rome | 04/27 12:25 | 25 | [174] Lorenzo Giustino v Juan P Varillas [150] | 6-1,7-5 | |
| Challenger Rome | 04/23 13:05 | 27 | [179] Lorenzo Giustino v Vit Kopriva [287] | 6-1,5-7,3-6 | |
| Challenger Rome | 04/22 09:00 | 26 | [179] Lorenzo Giustino v Sergiy Stakhovsky [211] | 6-4,6-4 | |
| Challenger Rome | 04/21 09:00 | 25 | [179] Lorenzo Giustino v Filip Horansky [178] | 7-6,7-5 | |
| Challenger Split | 04/13 15:20 | 25 | [204] Andrea Collarini v Lorenzo Giustino [168] | 6-4,6-4 | |
| ATP Mardella | 04/05 10:00 | 19 | [135] Henri Laaksonen v Lorenzo Giustino [170] | 7-5,3-6,6-1 | |
| ATP Mardella | 04/04 10:00 | 14 | [190] Roberto Marcora v Lorenzo Giustino [164] | 6-7,4-6 | |
| Challenger Marbella | 03/30 09:00 | 25 | [196] Mario Vilella Martinez v Lorenzo Giustino [164] | 7-6,6-0 | |
| ATP Miami | 03/22 16:00 | 14 | [204] Mitchell Krueger v Lorenzo Giustino [164] | 6-4,6-3 | |
| ATP Dubai | 03/16 12:50 | 25 | [163] Lorenzo Giustino v Aljaz Bedene [59] | 4-6,3-6 | |
| ATP Dubai | 03/14 07:00 | 19 | [96] Mikhail Kukushkin v Lorenzo Giustino [162] | 6-2,6-2 | |
| ATP Dubai | 03/13 10:55 | 14 | [322] Andrea Vavassori v Lorenzo Giustino [162] | 3-6,3-6 | |
| Challenger Biella | 03/11 10:30 | 26 | [216] Brayden Schnur v Lorenzo Giustino [162] | 6-4,6-2 | |
| Challenger Biella | 03/09 15:05 | 25 | [162] Lorenzo Giustino v Yasutaka Uchiyama [109] | 7-5,6-4 | |
| Challenger Gran Canaria | 03/02 10:00 | 25 | [160] Lorenzo Giustino v Enzo Couacaud [187] | 6-7,7-5,1-6 | |
| Challenger Gran Canaria | 02/23 10:00 | 25 | [158] Lorenzo Giustino v Roberto Ortega-Olmedo [297] | 6-1,3-6,4-6 |
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.