| Challenger - Tenerife | 01/19 15:00 | 26 | [220] Kimmer Coppejans v Lorenzo Giustino [267] | 3-6,3-6 | |
| Challenger - Tenerife | 01/17 16:20 | 25 | [199] Stefan Kozlov v Lorenzo Giustino [267] | Retired | |
| Challenger - Tenerife | 01/16 10:00 | 19 | [331] Alibek Kachmazov v Lorenzo Giustino [267] | 4-6,0-6 | |
| Challenger - Tenerife | 01/15 10:00 | 14 | [340] Maxime Janvier v Lorenzo Giustino [282] | 3-6,4-6 | |
| Challenger - Oeiras | 01/12 11:00 | 27 | [266] Joris De Loore v Lorenzo Giustino [282] | 6-2,6-4 | |
| Challenger - Oeiras | 01/11 11:00 | 26 | [282] Lorenzo Giustino v Jay Clarke [241] | 6-3,7-6 | |
| Challenger - Oeiras | 01/10 12:10 | 25 | [318] Elmar Ejupovic v Lorenzo Giustino [282] | 4-6,5-7 | |
| Challenger - Oeiras | 01/05 11:00 | 26 | [280] Raphael Collignon v Lorenzo Giustino [281] | 6-2,7-6 | |
| Challenger - Oeiras | 01/03 13:10 | 25 | [281] Lorenzo Giustino v Pol M Tiffon [293] | 6-1,3-6,6-3 | |
| Challenger - Maspalomas | 12/02 10:00 | 27 | [417] Pablo Llamas Ruiz v Lorenzo Giustino [305] | 6-4,7-6 | |
| Challenger - Maspalomas | 11/30 12:40 | 26 | [305] Lorenzo Giustino v Lukas Neumayer [304] | 6-3,7-5 | |
| Challenger - Maspalomas | 11/29 09:30 | 25 | [305] Lorenzo Giustino v Viktor Durasovic [342] | 7-5,6-4 | |
| Challenger - Ortisei | 10/25 13:30 | 25 | [167] Flavio Cobolli v Lorenzo Giustino [285] | 7-6,6-4 | |
| ATP - Napoli | 10/16 12:35 | 14 | [126] Francesco Passaro v Lorenzo Giustino [277] | 6-3,4-6,6-4 | |
| ATP - Gijon | 10/09 15:05 | 19 | [277] Lorenzo Giustino v Nicolas Alvarez Varona [228] | 2-6,2-6 | |
| ATP - Gijon | 10/08 16:15 | 14 | Dimitar Kuzmanov v Lorenzo Giustino | Walkover | |
| Challenger Alicante | 10/05 09:00 | 26 | [277] Lorenzo Giustino v Fabian Marozsan [185] | 2-6,6-3,1-6 | |
| Challenger Alicante | 10/04 09:00 | 25 | [352] Stuart Parker v Lorenzo Giustino [277] | 6-4,4-6,1-6 | |
| ATP - Tel Aviv | 09/25 08:55 | 14 | [443] Edan Leshem v Lorenzo Giustino [246] | 6-3,6-1 | |
| Challenger - Braga | 09/19 14:00 | 25 | [152] Manuel Guinard v Lorenzo Giustino [246] | 6-2,6-4 | |
| Challenger - Istanbul | 09/15 10:30 | 26 | [263] Harold Mayot v Lorenzo Giustino [253] | 7-5,7-5 | |
| Challenger - Istanbul | 09/13 11:05 | 25 | [253] Lorenzo Giustino v Dominik Palan [477] | 6-2,6-2 | |
| Challenger - Sevilia | 09/05 15:00 | 25 | [256] Lorenzo Giustino v Facundo D Acosta [249] | 6-7,6-4,1-6 | |
| Challenger - Toulouse | 08/29 14:30 | 25 | [254] Frederico F Silva v Lorenzo Giustino [256] | 6-7,6-3,6-4 | |
| Challenger - Banja Luka | 08/22 15:00 | 25 | Jan Choinski v Lorenzo Giustino | 6-2,7-6 | |
| Challenger - San Marino | 08/11 19:55 | 26 | [253] Lorenzo Giustino v Alexander Weis [423] | 2-6,5-7 | |
| 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 |
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.