Joao Fonseca is in Argentina preparing to defend his Buenos Aires Open title.
Fonseca won his first ATP Tour title at the Buenos Aires Open 12 months ago, defeating Argentine star Francisco Cerundolo in the final.
After struggling with physical issues during a first round loss at the Australian Open, the Brazilian has claimed he is back at 100 per cent fitness.
Joao Fonseca will be the man to unsettle Carlos Alcaraz and Jannik Sinner’s duopoly over men’s tennis – Prove us wrong!
The 19-year-old has been viewed as a future star of the sport ever since his breakout performance at the 2025 Australian Open; and since then, he has won another title in Switzerland and broken into the ATP’s top 25 ranked players.
Fonseca is certainly not afraid to vocalise his ambitions; and, as Andy Murray argued, he could be the man to challenge the dominance of Carlos Alcaraz and Jannik Sinner.
Joao Fonseca wants to become the world number one
Ahead of the Argentine event, Fonseca spoke to reporters in Buenos Aires about his 2025 season, while also discussing his future ambitions.
“2025 was a great year, I started very well after the Next Gen, winning Canberra and then winning here in Buenos Aires,” Fonseca said.
“During the year I had ups and downs, more ups than downs, but I had moments when I had more pressure and expectations.
“At the end of the year I won Basel, which was my first ATP 500, and I ended the year much more mature and knowing how to deal more with this level.
“Every time I have to work harder to climb the ranking and fulfill my dream, which is to be number one and win Grand Slams.”
Fonseca, the third seed in Buenos Aires, has been granted a bye through to the second round, where he will face Alejandro Tabilo or Facundo Diaz Acosta.
If the Brazilian advances further, he will play Tomas Etcheverry, Laslo Djere or Roman Andres Burruchaga in the quarter-finals.
If Fonseca advances to the last four, he will likely play Francisco Cerundolo, whom the Brazilian beat in last year’s final.
- 18-year-old Joao Fonseca stunned Andrey Rublev in straight sets at the 2025 Australian Open, eventually reaching the third round.
- He then won his first ATP Tour title at the Buenos Aires Open in February, defeating Francisco Cerundolo in the final.
- In October, the Brazilian won his second title in Basel, defeating Alejandro Davidovich Fokina in the final.
- Fonseca ended the 2025 season ranked 24th on the ATP Tour.
The youngest world number one in tennis history
Carlos Alcaraz became the youngest world number one in men’s tennis history after he won his first Grand Slam title at the 2022 US Open.
The Spaniard was aged 19 years and 131 days when he lifted the trophy in New York, usurping Lleyton Hewitt in the process.
Hewitt previously held the record, having become world number one aged 20 years and 268 days after winning his final group stage match at the 2001 ATP Finals.
Which member of the ‘Big Three’ is Carlos Alcaraz most similar to? Let us know why below👇
Marat Safin is in third spot, having achieved world number one status at 20 years and 298 days after winning the 2000 Paris Masters.
John McEnroe, Andy Roddick, Bjorn Borg, Jim Courier, Pete Sampras, Jimmy Connors and Rafael Nadal round out the top 10.
