| Challenger - Lugano | 03/27 12:35 | 14 | [299] Ruben Bemelmans v Giovanni Fonio [416] | 7-5,6-4 | |
| ITF - M25 - Opatija | 03/22 10:45 | 25 | [489] Francesco Passaro v Giovanni Fonio [414] | 6-0,4-6,6-2 | |
| ITF - M25 - Rovinj | 03/15 12:35 | 25 | [362] Ergi Kirkin v Giovanni Fonio [414] | 6-4,7-6 | |
| ITF - M25 - Porec | 03/09 10:45 | 25 | [335] Filip Misolic v Giovanni Fonio [414] | 7-6,6-4 | |
| ITF - M25 - Antalya | 02/26 09:15 | 27 | [367] Daniel Michalski v Giovanni Fonio [408] | 6-3,4-6,7-5 | |
| ITF - M25 - Antalya | 02/25 12:30 | 26 | Giovanni Fonio v Andrea Picchione | Retired | |
| ITF - M25 - Antalya | 02/22 11:00 | 25 | Togan Tokac v Giovanni Fonio | 1-6,1-6 | |
| ITF - M25 - Antalya | 02/15 11:25 | 25 | [330] Miljan Zekic v Giovanni Fonio [412] | 6-2,6-4 | |
| ITF - M15 - Antalya | 01/29 15:15 | 27 | [411] Giovanni Fonio v Corentin Denolly [450] | 6-7,2-6 | |
| ITF - M15 - Antalya | 01/29 11:30 | 26 | Giovanni Fonio v S Mert Ozdemir | 6-2,6-2 | |
| ITF - M15 - Antalya | 01/28 09:00 | 25 | Giovanni Fonio v Juan P Canas Garcia | 7-5,6-2 | |
| ITF - M15 - Antalya | 01/23 08:50 | 29 | [479] Cezar Cretu v Giovanni Fonio [411] | 1-6,4-6 | |
| ITF - M15 - Antalya | 01/22 10:00 | 28 | Giovanni Fonio v Davide Galoppini | 6-1,6-2 | |
| ITF - M15 - Antalya | 01/21 13:00 | 27 | Paul Woerner v Giovanni Fonio | 1-6,3-6 | |
| ITF - M15 - Antalya | 01/20 15:00 | 26 | Calin Manda v Giovanni Fonio | 4-6,3-6 | |
| ITF - M15 - Antalya | 01/19 12:40 | 25 | Aleksandar Tomas v Giovanni Fonio | 2-6,2-6 | |
| Challenger - Antalya | 12/11 10:00 | 28 | [409] Oleg Prihodko v Giovanni Fonio [441] | 1-6,6-1,6-3 | |
| Challenger - Antalya | 12/10 07:00 | 27 | [441] Giovanni Fonio v Nick Hardt [350] | 7-6,6-2 | |
| Challenger - Antalya | 12/09 09:25 | 26 | [264] Ryan Peniston v Giovanni Fonio [441] | 6-1,4-6,4-6 | |
| Challenger - Antalya | 12/08 12:30 | 25 | [466] Jakub Paul v Giovanni Fonio [441] | 1-6,0-6 | |
| Challenger - Antalya | 11/29 07:30 | 14 | Marsel Ilhan v Giovanni Fonio | 6-4,3-6,6-4 | |
| Challenger - Napoli | 10/11 08:00 | 14 | [303] Javier Barranco Cosano v Giovanni Fonio [437] | 7-5,6-3 | |
| ITF - M15 - Platja D'Aro | 10/09 09:00 | 28 | [437] Giovanni Fonio v Jose Fco. Vidal Azorin [476] | 3-6,4-6 | |
| ITF - M15 - Platja D'Aro | 10/08 10:00 | 27 | Giovanni Fonio v Maxime Chazal | 6-3,6-2 | |
| ITF - M15 - Platja D'Aro | 10/07 13:35 | 26 | Giovanni Fonio v Manish Sureshkumar | 6-0,6-1 | |
| ITF - M15 - Platja D'Aro | 10/06 10:15 | 25 | Giovanni Fonio v Vitali Shvets | 6-4,6-0 | |
| Challenger - Lissabon | 09/26 14:00 | 14 | [458] Daniel Michalski v Giovanni Fonio [439] | 6-4,7-5 | |
| Challenger - Bukarest | 09/19 07:30 | 14 | [436] Giovanni Fonio v Oleksii Krutykh [380] | 3-6,1-6 | |
| Challenger - Triest | 07/26 12:35 | 19 | [328] Thiago A Tirante v Giovanni Fonio [442] | 6-3,6-3 | |
| Challenger - Triest | 07/25 11:35 | 14 | [438] Giovanni Fonio v Julian Ocleppo [360] | 3-6,6-4,7-5 |
Giovanni Fonio (* 7. Mai 1998 in Novara) ist ein italienischer Tennisspieler.