By SABC Sport
15th January 2025
The Brazilian became only the second teenager to beat a top-10 player in their first-ever major match since the ATP Rankings was introduced in 1973.
Fonseca finished the 2024 season on a high after winning the Next Gen ATP Finals and ended the year at No 145 in the world rankings.
He rose to No 112 ahead of the start of the Australian Open, but is now set to surge into the top 100 after the 7-6 (7-1), 6-3, 7-6 (7-5) victory over Rublev.
Carlos Alcaraz became the youngest world No 1 at the age of 19 and has predicted a bright future in the game for Fonseca.
The four-time Grand Slam winner said: "I saw it. I saw a little bit. I couldn't watch the whole match. I saw a little bit at the beginning and the end of the match.
"What can I say about it? Just incredible. I mean, the way he played his first Grand Slam match against his first top 10 [opponent], it's unbelievable.
"The way he approached the match, the way he handled everything, the nerves, the match in general, it's been fantastic.
"It's someone that I have to be careful of, let's say⦠He's going to be there. It is just the beginning of the year, just one win in [a] Grand Slam, but he's going to be there.
"We're going to put Joao Fonseca's name on the list of the best players in the world really soon."