| ITF Italy F33 | 10/10 12:55 | 25 | [295] Walter Trusendi v Lorenzo Giustino [261] | 3-6,6-7 | |
| Challenger Rome 2 | 09/26 09:00 | 25 | Lorenzo Giustino v Patricio Heras | 1-6,3-6 | |
| Challenger Sibiu | 09/18 09:00 | 25 | [129] Stefano Travaglia v Lorenzo Giustino [198] | 6-2,6-0 | |
| Challenger Banja Luka | 09/13 08:00 | 25 | [313] Tomislav Brkic v Lorenzo Giustino [198] | 6-4,6-4 | |
| ITF Italy F28 | 09/05 14:30 | 25 | Lorenzo Giustino v Roberto Marcora | 3-6,4-6 | |
| US Open Qual | 08/23 20:35 | 44 | [254] Stephane Robert v Lorenzo Giustino [189] | 6-4,6-2 | |
| Challenger Cordenons | 08/19 17:00 | 28 | [279] Elias Ymer v Lorenzo Giustino [197] | 6-2,6-1 | |
| Challenger Cordenons | 08/18 18:15 | 27 | Lorenzo Giustino v Andrea Pellegrino | 6-3,6-3 | |
| Challenger Cordenons | 08/17 12:00 | 26 | [197] Lorenzo Giustino v Daniel M.-De La Nava [418] | 3-6,6-2,6-3 | |
| Challenger Cordenons | 08/15 14:35 | 25 | [197] Lorenzo Giustino v Gianluigi Quinzi [260] | 4-6,6-2,6-1 | |
| Challenger Portoroz | 08/08 08:00 | 25 | [199] Lorenzo Giustino v Matteo Berrettini [162] | 6-3,3-6,4-6 | |
| Challenger Biella | 08/01 08:00 | 25 | Constant Lestienne v Lorenzo Giustino | 7-5,4-6,6-4 | |
| ATP Gstaad | 07/24 14:30 | 25 | [192] Lorenzo Giustino v Denis Istomin [82] | 3-6,2-6 | |
| ATP Gstaad Qual | 07/23 11:15 | 46 | [137] Joao Souza v Lorenzo Giustino [182] | 6-7,6-7 | |
| ATP Gstaad Qual | 07/22 11:50 | 45 | [409] Yann Marti v Lorenzo Giustino [182] | 4-6,7-6,2-6 | |
| Challenger San Benedetto | 07/18 14:40 | 25 | [182] Lorenzo Giustino v Carlos Taberner [301] | 3-6,5-7 | |
| Challenger Perugia | 07/11 09:00 | 25 | [168] Lorenzo Giustino v Gleb Sakharov [205] | 6-7,2-6 | |
| Challenger Marburg | 07/03 11:30 | 25 | [299] Joao Pedro Sorgi v Lorenzo Giustino [168] | 6-7,6-3,7-6 | |
| Wimbledon Qual | 06/26 10:00 | 44 | [119] Darian King v Lorenzo Giustino [168] | 6-4,6-0 | |
| Challenger Lyon | 06/12 16:00 | 25 | [167] Lorenzo Giustino v Casper Ruud [112] | 4-6,0-6 | |
| Challenger Prostejov | 06/06 09:00 | 25 | [175] Lorenzo Giustino v Joao Souza [140] | 5-7,7-6,3-6 | |
| Challenger Vicenza | 06/03 11:30 | 28 | [175] Lorenzo Giustino v Laslo Djere [135] | 4-6,6-2,3-6 | |
| Challenger Vicenza | 06/02 09:30 | 27 | Daniel Munoz-De La Nava v Lorenzo Giustino | 6-3,3-6,2-6 | |
| Challenger Vicenza | 05/31 13:00 | 26 | [199] Salvatore Caruso v Lorenzo Giustino [175] | 1-6,2-6 | |
| Challenger Vicenza | 05/29 15:45 | 25 | [175] Lorenzo Giustino v Guido Andreozzi [124] | 6-3,6-2 | |
| French Open Qual | 05/22 11:55 | 44 | [175] Lorenzo Giustino v Stefano Napolitano [185] | 4-6,4-6 | |
| Challenger Heilbronn | 05/20 16:50 | 28 | [186] Lorenzo Giustino v Norbert Gombos [100] | 3-6,5-7 | |
| Challenger Heilbronn | 05/20 10:45 | 27 | [186] Lorenzo Giustino v Andrej Martin [110] | 6-3,7-5 | |
| Challenger Heilbronn | 05/18 17:30 | 26 | [377] Dominik Koepfer v Lorenzo Giustino [186] | 6-7,6-1,1-6 | |
| Challenger Heilbronn | 05/16 14:00 | 25 | [174] Dennis Novikov v Lorenzo Giustino [186] | 4-6,4-6 |
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.