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.

At just 18, João Fonseca is putting the tennis world on notice, as illustrated by his clinical straight-sets victory over ninth seed Andrey Rublev at the Australian Open.

Rising Brazilian tennis star Joao Fonseca has made a stunning debut on the Grand Slam circuit, defeating Andrey Rublev at the 2025 Australian Open. This is Rublev's first opening-round defeat at Melbourne Park since 2019.