| ITF M25 Santa Margherita | 09/28 16:30 | 26 | Giovanni Fonio v Fabrizio Andaloro | 6-2,6-4 | |
| ITF M25 Santa Margherita | 09/27 17:35 | 25 | Giovanni Fonio v Federico Bertuccioli | 6-4,6-1 | |
| Challenger Sibiu | 09/22 09:00 | 26 | [288] Ivan Gakhov v Giovanni Fonio [372] | 6-4,6-2 | |
| Challenger Sibiu | 09/20 12:00 | 25 | Dragos Nicolae Madaras v Giovanni Fonio | 1-6,4-6 | |
| Challenger Sibiu | 09/19 08:55 | 19 | [373] Giovanni Fonio v Eric Vanshelboim [489] | 6-3,6-1 | |
| Challenger Sibiu | 09/18 10:15 | 14 | Giovanni Fonio v Vlad Andrei Dancu | 6-2,6-3 | |
| Challenger Seville | 09/07 15:00 | 26 | [403] Giovanni Fonio v Bernabe Zapata Miralles [79] | 6-7,4-6 | |
| Challenger Seville | 09/06 10:35 | 25 | [403] Giovanni Fonio v Dalibor Svrcina [222] | 6-3,6-1 | |
| Challenger Seville | 09/05 10:40 | 19 | [285] Oriol Roca Batalla v Giovanni Fonio [403] | 2-6,1-6 | |
| Challenger Seville | 09/04 14:05 | 14 | [403] Giovanni Fonio v Andrey Chepelev [346] | 6-3,6-4 | |
| Challenger Como | 08/29 08:00 | 19 | [311] Nicolas M D Alboran v Giovanni Fonio [403] | 7-6,4-6,6-3 | |
| Challenger Como | 08/28 08:00 | 14 | Lorenzo Ferri v Giovanni Fonio | 0-6,2-6 | |
| ITF M25 Lesa | 08/23 19:55 | 25 | Gabriele Piraino v Giovanni Fonio | 6-3,7-6 | |
| ITF M25 Muttenz | 08/18 11:15 | 26 | Jan Sebesta v Giovanni Fonio | 6-3,6-3 | |
| ITF M25 Muttenz | 08/18 07:00 | 25 | Jeffrey Von Der Schulenburg v Giovanni Fonio | 5-7,6-7 | |
| Challenger San Benedetto | 07/29 17:55 | 27 | [435] Giovanni Fonio v Luciano Darderi [186] | 4-6,1-6 | |
| Challenger San Benedetto | 07/28 19:30 | 26 | [435] Giovanni Fonio v Frederico Ferreira Silva [249] | 6-4,6-1 | |
| Challenger San Benedetto | 07/26 19:55 | 25 | [231] Alessandro Giannessi v Giovanni Fonio [435] | 3-6,4-6 | |
| Challenger San Benedetto | 07/25 11:00 | 19 | [471] Luca Potenza v Giovanni Fonio [435] | 2-6,3-6 | |
| Challenger San Benedetto | 07/24 13:10 | 14 | [488] Riccardo Balzerani v Giovanni Fonio [436] | 6-2,3-6,4-6 | |
| Challenger Trieste | 07/18 09:00 | 19 | [345] Lukas Neumayer v Giovanni Fonio [436] | 3-6,7-6,6-2 | |
| Challenger Trieste | 07/17 08:00 | 14 | Alessandro Pecci v Giovanni Fonio | 7-6,2-6,6-7 | |
| Challenger Verona | 07/10 13:30 | 14 | [333] Pedro B Dias v Giovanni Fonio [441] | 7-5,1-6,7-5 | |
| Challenger Todi | 07/06 13:00 | 26 | [232] Luciano Darderi v Giovanni Fonio [441] | 6-3,7-6 | |
| Challenger Todi | 07/05 11:05 | 25 | [441] Giovanni Fonio v Dmitry Popko [195] | 6-4,3-6,6-1 | |
| Challenger Todi | 07/04 10:20 | 19 | [333] Pedro B Dias v Giovanni Fonio [441] | 3-6,2-6 | |
| Challenger Todi | 07/03 11:25 | 14 | Mohamed Safwat v Giovanni Fonio | 0-6,1-6 | |
| Challenger Troyes | 06/27 15:00 | 19 | [367] Clement Tabur v Giovanni Fonio [441] | 6-7,7-5,7-6 | |
| Challenger Troyes | 06/26 14:05 | 14 | Boris Fassbender v Giovanni Fonio | 0-6,2-6 | |
| Challenger Milan | 06/22 13:20 | 26 | [457] Giovanni Fonio v Alexander Shevchenko [173] | 3-6,6-7 |
Giovanni Fonio (born 7 May 1998) is an Italian tennis player. He took his first steps in tennis at the age of 5, at the Piazzano tennis club in Novara.
Fonio has a career high ATP singles ranking of 274 achieved on 4 Dicember 2023. He also has a career high doubles ranking of 406 achieved on 15 January 2024.
Fonio has won 2 ATP Challenger doubles title: at the 2023 Internazionali di Tennis del Friuli Venezia Giulia with Francesco Forti and at the 2021 Antalya Challenger III with Riccardo Bonadio.
The greatest victory achieved by Giovanni was certainly during the Yokkaichi Challenger in Japan, on 30 November 2023, when he beat the then top 100 player Yosuke Watanuki in 3 sets (3-6 / 6-2 / 7-5).
An important presence in high-level tournaments was certainly in May 2022 at the qualifiers at the Internazionali d’Italia, unfortunately he lost against Emil Ruusuvuori 2-1 (4-6 / 7-6 / 3-6).