In his first-ever Grand Slam match, Fonseca defeated World No. 9 Andrey Rublev in straight sets: 7-6 (1), 6-3, 7-6 (5). The match was evenly contested, but Fonseca was dominant with his power and agility.

In a highly entertaining Australian Open first round match, 18-year-old Joao Fonseca defeated ninth ranked Andrey Rublev.

During the match against Rublev, Joao showed all his power from baseline by shooting a forehand winner at 181 km/h. His forehand is the fastest in this edition of the tournament so far, ahead of Mpetshi Perricard (180 km/h) and Carlitos Alcaraz (178 km/h).