| Challenger Tenerife | 02/18 10:00 | 14 | [277] Giovanni Fonio v Lorenzo Giustino [330] | 4-6,6-4,6-1 | |
| Challenger Cherbourg | 02/12 17:10 | 25 | [330] Lorenzo Giustino v Mattia Bellucci [193] | 6-7,3-6 | |
| Challenger Nottingham | 02/06 10:30 | 25 | [183] Alexander Ritschard v Lorenzo Giustino [329] | 6-4,6-3 | |
| Challenger Quimper | 01/22 11:20 | 14 | Lorenzo Giustino v Emilien Voisin | 6-3,3-6,4-6 | |
| Challenger Tenerife | 01/15 10:00 | 19 | [300] Lorenzo Giustino v Samuel Vincent Ruggeri [337] | 2-6,3-6 | |
| Challenger Tenerife | 01/14 11:20 | 14 | [288] Lorenzo Giustino v Alberto Barroso Campos [380] | 6-4,6-2 | |
| Challenger Oeiras | 01/10 15:40 | 26 | [244] Joao Sousa v Lorenzo Giustino [288] | 6-3,6-1 | |
| Challenger Oeiras | 01/09 13:30 | 25 | [288] Lorenzo Giustino v Michael Vrbensky [301] | 6-4,2-6,7-5 | |
| Challenger Oeiras | 01/04 15:00 | 26 | [322] Thai-Son Kwiatkowski v Lorenzo Giustino [287] | 6-4,6-4 | |
| Challenger Oeiras | 01/01 17:20 | 25 | [287] Lorenzo Giustino v Michael Vrbensky [300] | 7-5,4-6,6-4 | |
| 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 | |
| ATP Sofie | 11/04 13:30 | 14 | [274] Lorenzo Giustino v Illya Marchenko [210] | 6-7,7-6,3-6 | |
| Challenger Šen-čen | 10/20 05:25 | 27 | [290] Lorenzo Giustino v Aleksandar Kovacevic [112] | 3-6,6-3,3-6 | |
| Challenger Šen-čen | 10/19 07:55 | 26 | [362] Colin Sinclair v Lorenzo Giustino [290] | 3-6,4-6 | |
| Challenger Šen-čen | 10/16 05:10 | 26 | [290] Lorenzo Giustino v Rigele Te [482] | 6-4,6-3 | |
| Challenger Šen-čen | 10/11 02:00 | 25 | [278] Lorenzo Giustino v Terence Atmane [148] | 6-7,3-6 | |
| ATP Šanghaj | 10/02 05:55 | 14 | [344] Benjamin Lock v Lorenzo Giustino [279] | 7-6,3-6,6-4 | |
| ATP Ču-chaj | 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 Šanghaj | 09/08 05:50 | 27 | [296] Lorenzo Giustino v Juncheng Shang [178] | 1-6,4-6 | |
| Challenger Šanghaj | 09/07 03:00 | 26 | [214] Yunchaokete Bu v Lorenzo Giustino [296] | 1-6,4-6 | |
| Challenger Šanghaj | 09/05 03:00 | 25 | [346] Hiroki Moriya v Lorenzo Giustino [296] | 1-6,2-6 | |
| Challenger Zhangjiagang | 08/31 06:20 | 26 | [296] Lorenzo Giustino v James McCabe [281] | 4-6,6-3,1-6 | |
| Challenger Zhangjiagang | 08/30 04:45 | 25 | Leonid Sheyngezikht v Lorenzo Giustino | 4-6,1-6 | |
| Challenger Praha | 08/23 09:45 | 26 | [425] Federico Agustin Gomez v Lorenzo Giustino [300] | 6-3,6-3 | |
| Challenger Praha | 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 |
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.