Brazilian wonderkid João Fonseca (99 ATP singles ranked) made history on Sunday when he beat Argentina’s Francisco Cerúndolo (28) 6-4, 7-6 (1) to become the 2025 Argentina Open champion. At 18 years and 5 months old, the Brazilian became the youngest player to win the tournament, beating current world number three Carlos Alcaraz’s record by a year and four months.

“This tournament was a big step for me,” said Fonseca after the match. “When you get here, you take a look at the draw and think ‘It’s impossible to win this,’ and here we are. It’s a very important title for me, the first one, and it’ll be forever in my heart.”

It was a tense match from the get-go. With tickets sold out (5,746 fans in attendance), the big contingent of Brazilian fans in the stands kept the Argentine crowd in check.

Cerúndolo started off very erratic, with a series of unforced errors costing him his serve in the first game. He quickly broke Fonseca’s serve to equalize the game but struggled to replicate his decisive performance in Saturday’s semi-final. Mistakes cost him again at 3-3, helping the Brazilian to a lead that he didn’t relinquish, as he closed the first set out with his serve.

A tense second set

The game continued in a similar vein in the second set, where again, unforced errors and bad decision-making cost Cerúndolo at 2-2. Despite having chances to equalize the game, he failed to take them. 

Tensions skyrocketed in the final games. With Fonseca serving at 5-4 to wrap up the game, however, he finally felt the weight of the match. A couple of mistakes allowed Cerúndolo to tie the game, but he failed to hold his serve again the next game. This prompted euphoric celebrations from the Brazilian fans, sparking altercations in the stands with the Argentine crowd.

Fonseca once again failed to wrap the game at 6-5, sending the second set to a tie-break. There, the Brazilian finally showed the form that catapulted him to the decider. He took advantage of more erratic shot-making by Cerúndolo to breeze through the tiebreak and claim his first-ever ATP Tour title.

With his Buenos Aires title, Fonseca became the 10th youngest champion in ATP Tour history since 1990, kicking U.S. legend Pete Sampras from the top 10. He’s also the first man born in 2006 or later to win an ATP Tour title, and the youngest-ever South American man to win a tour-level title since Perez-Roldan lifted the 1987 Buenos Aires crown. His win also sees him jump to 68 in the ATP singles rankings, his best-ever position.

“It was a normal match,” said Cerúndolo at the press conference. “I didn’t play a great game but he also didn’t let me do much. His shots come very fast and he doesn’t let you play.”

“When you try to make big shots to put him on the back foot, you make more mistakes. I missed easy shots, and he has a great repertoire, with almost no gaps. I don’t know if I could’ve made anything different.”

The Argentine admitted having played most of his games at night, he found a quicker court where the ball bounced faster, and couldn’t make the necessary adjustments.

“I’ll try to take the best out of this week, but then put it behind and start thinking about Rio de Janeiro,” he said.

Fonseca highlighted the support he had from the Brazilian fans in the stands, thanking them for their support all week.

“I think every kid who plays a sport wants to be the best,” he said. “I started playing when I was four, thanks to my dad. When I started playing tournaments at eight years old, even though I played other sports, that’s when I started dreaming of becoming a world number one.