| Challenger - Francavilla | 05/08 11:00 | 19 | [291] Giovanni Fonio v Alexander Weis [338] | 6-1,6-2 | |
| Challenger - Francavilla | 05/07 09:00 | 14 | [304] Giovanni Fonio v Andrea Picchione [396] | 6-3,7-5 | |
| Challenger - Roma | 04/26 08:00 | 26 | [236] Marco Trungelliti v Giovanni Fonio [304] | 2-6,6-1,6-2 | |
| Challenger - Roma | 04/25 08:55 | 25 | [304] Giovanni Fonio v Mattia Bellucci [165] | 6-3,6-4 | |
| Challenger - Roma | 04/24 08:00 | 19 | Giovanni Fonio v Miguel Damas | 6-0,6-0 | |
| Challenger - Roma | 04/23 08:00 | 14 | Giovanni Fonio v Federico Salomone | 6-1,6-1 | |
| Challenger - Roseto | 04/18 14:00 | 25 | [361] Francesco Forti v Giovanni Fonio [306] | 7-6,6-2 | |
| Challenger - Barletta | 04/02 09:10 | 14 | [328] Giovanni Fonio v Julian Ocleppo [394] | 7-6,6-7,1-6 | |
| Challenger - Sanremo | 03/29 12:00 | 26 | [108] Luca Van Assche v Giovanni Fonio [328] | 6-3,6-3 | |
| Challenger - Sanremo | 03/28 08:00 | 25 | [415] Gianmarco Ferrari v Giovanni Fonio [328] | 1-6,6-7 | |
| Challenger - Sanremo | 03/27 08:00 | 19 | [319] Moez Echargui v Giovanni Fonio [328] | 6-7,3-6 | |
| Challenger - Sanremo | 03/26 08:00 | 14 | [442] Elliot Benchetrit v Giovanni Fonio [328] | 2-6,6-3,4-6 | |
| Challenger - Zadar | 03/21 09:00 | 25 | [328] Giovanni Fonio v Arthur Cazaux [218] | 6-4,4-6,2-6 | |
| Challenger - Zadar | 03/20 09:00 | 168 | [328] Giovanni Fonio v Damien Wenger [403] | 7-5,6-2 | |
| Challenger - Zadar | 03/19 10:30 | 45 | Giovanni Fonio v Patrik Jurina | 6-2,6-2 | |
| Challenger - Székesfehérvár | 03/12 09:00 | 14 | [341] Giovanni Fonio v Elliot Benchetrit [444] | Cancelled | |
| ITF - M25 Loulé | 03/04 13:50 | 28 | Giovanni Fonio v Lucas Poullain | 4-6,6-7 | |
| ITF - M25 Loulé | 03/03 14:50 | 27 | Adria Soriano Barrera v Giovanni Fonio | 2-6,4-6 | |
| ITF - M25 Loulé | 03/02 13:30 | 26 | Guy Den Ouden v Giovanni Fonio | 4-6,4-6 | |
| ITF - M25 Loulé | 03/01 15:45 | 25 | Tiago Pereira v Giovanni Fonio | 4-6,6-7 | |
| ITF - M25 Faro | 02/23 12:40 | 26 | [486] August Holmgren v Giovanni Fonio [332] | 6-2,3-6,7-5 | |
| ITF - M25 Faro | 02/21 11:55 | 25 | [473] Goncalo Oliveira v Giovanni Fonio [332] | 6-7,4-6 | |
| Challenger - Tenerife | 02/10 13:15 | 27 | [159] Ryan Peniston v Giovanni Fonio [364] | 7-5,6-2 | |
| Challenger - Tenerife | 02/09 11:00 | 26 | [364] Giovanni Fonio v Bu Yunchaokete [282] | 7-6,6-4 | |
| Challenger - Tenerife | 02/07 12:30 | 25 | [351] Christian Harrison v Giovanni Fonio [364] | 5-7,4-6 | |
| Challenger - Tenerife - Qualificação | 02/06 13:05 | 19 | [232] Matteo Gigante v Giovanni Fonio [364] | 4-6,4-6 | |
| Challenger - Tenerife - Qualificação | 02/06 10:00 | 14 | Alessio De Bernardis v Giovanni Fonio | 0-6,1-6 | |
| Challenger - Tenerife | 01/29 10:00 | 14 | [267] Lorenzo Giustino v Giovanni Fonio [366] | 6-3,6-4 | |
| Challenger - Nonthaburi | 01/21 03:30 | 28 | [366] Giovanni Fonio v Arthur Cazaux [265] | 5-7,3-6 | |
| Challenger - Nonthaburi | 01/20 05:25 | 27 | [366] Giovanni Fonio v Antoine Escoffier [192] | Retired |
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).