Fonseca was ranked 730th in the world at the start of 2024, but by the end of the year he had surged up the rankings into the top 150.

He captured tennis fans' attention with quarter-final runs at the ATP 500 event in his home city of Rio de Janeiro and at the ATP 250 in Bucharest.

The teenager truly established himself as one of the best newcomers by winning December's Next Gen ATP Finals - an event for the best male players aged 21 and under.

Current world number one Jannik Sinner, who won the tournament in 2019, is the only player to have lifted the title at a younger age than Fonseca.

In fact, it was Sinner who convinced Fonseca to turn professional when he was a hitting partner for the Italian at the 2023 ATP Finals.

Fonseca's showing against Rublev proved his potential, as he took charge with his powerful forehand and fired home 51 winners to the Russian's 33.

"I just enjoyed every moment on this amazing court, it's my first time playing in a huge stadium," Fonseca said.

Fonseca is just the second teenager since 1973 to beat a top-10 opponent at their maiden Grand Slam, after Mario Ancic beat Roger Federer at Wimbledon in 2002.

Asked in his on-court interview how much money it would cost to have his talent, Fonseca referenced 20-time major winner Federer, replying: "Like Roger said, talent is not enough without hard work.

"My idol was always Roger, I grew up watching Roger. Everyone wanted to play like him and I even tried when I was younger the one-handed [backhand] for one week."

Fonseca will meet Italy's Lorenzo Sonego, who is ranked 57 places higher, in the second round on Thursday.

"Of course my expectations are bigger now," Fonseca said. "I want more and more, I think that is the mentality of champions."