| Challenger Maspalomas | 11/27 13:45 | 25 | [386] Gerard Campana Lee v Lorenzo Giustino [276] | 4-6,6-1,6-3 | |
| Challenger Valencia | 11/19 12:30 | 14 | Nicolas Alvarez Varona v Lorenzo Giustino | 6-4,6-4 | |
| Sofia, Bulgaria | 11/04 13:30 | 14 | [274] Lorenzo Giustino v Illya Marchenko [210] | 6-7,7-6,3-6 | |
| Challenger - Shenzhen | 10/20 05:25 | 27 | [290] Lorenzo Giustino v Aleksandar Kovacevic [112] | 3-6,6-3,3-6 | |
| Challenger - Shenzhen | 10/19 07:55 | 26 | [362] Sinclair, Colin v Lorenzo Giustino [290] | 3-6,4-6 | |
| Challenger - Shenzhen | 10/16 05:10 | 26 | [290] Lorenzo Giustino v Rigele Te [482] | 6-4,6-3 | |
| Challenger - Shenzhen | 10/11 02:00 | 25 | [278] Lorenzo Giustino v Terence Atmane [148] | 6-7,3-6 | |
| Shanghai, Chine | 10/02 05:55 | 14 | [344] Benjamin Lock v Lorenzo Giustino [279] | 7-6,3-6,6-4 | |
| Zhuhai, Chine | 09/19 04:30 | 14 | [281] Lorenzo Giustino v Alex Bolt [323] | 4-6,3-6 | |
| Challenger - Guangzhou | 09/12 03:50 | 25 | [279] Lorenzo Giustino v Terence Atmane [173] | 0-6,6-4,3-6 | |
| Challenger Shanghai | 09/08 05:50 | 27 | [296] Lorenzo Giustino v Juncheng Shang [178] | 1-6,4-6 | |
| Challenger Shanghai | 09/07 03:00 | 26 | [214] Yunchaokete Bu v Lorenzo Giustino [296] | 1-6,4-6 | |
| Challenger Shanghai | 09/05 03:00 | 25 | [346] Hiroki Moriya v Lorenzo Giustino [296] | 1-6,2-6 | |
| Zhangjiagang, China | 08/31 06:20 | 26 | [296] Lorenzo Giustino v James McCabe [281] | 4-6,6-3,1-6 | |
| Zhangjiagang, China | 08/30 04:45 | 25 | Leonid Sheyngezikht v Lorenzo Giustino | 4-6,1-6 | |
| Challenger Prague | 08/23 09:45 | 26 | [425] Federico Agustin Gomez v Lorenzo Giustino [300] | 6-3,6-3 | |
| Challenger Prague | 08/21 11:50 | 25 | [300] Lorenzo Giustino v Filip Cristian Jianu [348] | 6-4,6-3 | |
| Challenger Todi | 08/15 16:35 | 25 | [301] Lorenzo Giustino v Mathys Erhard [310] | 6-7,0-6 | |
| Challenger Todi | 08/15 13:20 | 25 | Lorenzo Giustino v Camilo Ugo Carabelli | Cancelled | |
| Challenger Porto | 08/01 14:50 | 25 | [162] Antoine Escoffier v Lorenzo Giustino [290] | 6-3,6-4 | |
| Challenger Pozoblanco | 07/18 07:30 | 25 | Lorenzo Giustino v Edas Butvilas | 1-6,2-6 | |
| Challenger Salzburg | 07/10 10:30 | 19 | [258] Lorenzo Giustino v Sandro Kopp [453] | 0-6,2-6 | |
| Challenger Troyes | 07/07 15:30 | 27 | Calvin Hemery v Lorenzo Giustino | 6-4,4-6,6-1 | |
| Challenger Troyes | 07/06 11:00 | 26 | [331] Lucas Gerch v Lorenzo Giustino [258] | 3-6,6-3,3-6 | |
| Challenger Troyes | 07/05 10:05 | 25 | [295] Valentin Royer v Lorenzo Giustino [258] | 4-6,4-6 | |
| Challenger Modena | 06/26 17:40 | 25 | [256] Lorenzo Giustino v Nerman Fatic [251] | 6-7,2-6 | |
| Poznan, Poland | 06/20 08:30 | 25 | [117] Diaz Acosta, Facundo v Lorenzo Giustino [255] | 3-6,6-2,6-4 | |
| Challenger Perugia | 06/12 13:30 | 25 | [313] Pol M Tiffon v Lorenzo Giustino [250] | 6-3,6-3 | |
| Prostejov, Czech Republic | 06/04 11:25 | 14 | Lorenzo Giustino v Pedro Sakamoto | 6-4,6-7,6-7 | |
| Challenger Vicenza | 05/29 10:50 | 19 | [250] Lorenzo Giustino v Nerman Fatic [278] | 2-6,2-6 |
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.