Joao Fonseca did not just beat No. 9 seed Andrey Rublev at the 2025 Australian Open. The 18-year-old blew Rublev off the court in straight sets.
Combined with a NextGen ATP Finals triumph only a few weeks earlier, those results blasted expectations for Fonseca into a different stratosphere. How soon would he become a top-10 player? One year after winning the NextGen, would he be in the Nitto ATP Finals this time around?
It turned out that those kinds of ideas predictably proved to be delusions of grandeur.
As any season on the professional tour should be for any teenager, Fonseca’s 2025 campaign was a rocky ride. The bumps started immediately following his victory over Rublev, as the Brazilian lost his next match to Lorenzo Sonego — a five-setter in the Aussie Open second round. But the hype train wasn’t about to lose steam. Fonseca won his next tournament, capturing his first ATP title at the 250-point tournament on the red clay of Buenos Aires.
After departing Buenos Aires with the trophy, Fonseca was thoroughly mediocre from mid-February through the summer. Of his next 25 matches, he won 12 and lost 13.
Fonseca, who recently announced that he will not defend his NextGen AP Finals title, put an exclamation point on his season with an ATP 500 title in Basel at the end of October. That propelled him from 46th in the rankings to 28th, and he currently registers at a career-high 24th.
Was it perfect? No. Six first-round exits were arguably a bit too many, especially since half of them came against lower-ranked opponents. But such inconsistency can be forgiven for any teenager — even one of Fonseca’s incredible talent. Was it a smashing success overall? Absolutely. He is the youngest man in the Open Era to win an ATP 500 title and he is the youngest since 2011 to reach the Wimbledon third round.
Now for some comparisons. The highest-ranked player who is younger than Fonseca is No. 182 (Justin Engel); there is only one other teenager ranked better than No. 135 (No. 28 Learner Tien). Jannik Sinner finished his 19-year-old season with one ATP 250 title and a ranking of 44th. When Roger Federer was the same age that Fonseca is now, the Swiss had zero ATP titles and the exact same career-high ranking of No. 24. Novak Djokovic was on an eerily similar trajectory that Fonseca is now. Right after turning 19 (May of 2006), Djokovic won the first two ATP titles of his career and broke into the top 30 for the first time. Yes, the Spanish duo of Rafael Nadal and Carlos Alcaraz were ahead of that curve at 19 — but those are once-in-a-tennis-generation phenomenons.
If not A-plus, it was an A of a season for Fonseca by basically anyone and everyone’s standards. And it sets the stage for what should be a massive 2026. At No. 24 in the world, Fonseca is in a great spot to not only be seeded for the Australian Open (and the other three slams) but also seeded in the top 24 — which would crucially allow him to avoid any top-eight opponent until at least the fourth round. He should be seeded at almost every event he enters, which guarantees more favorable draws and sets him up for success week in and week out.
The ATP Tour could really use another slam-winning superstar to turn the current top two into this generation’s Big 3. Fonseca has a chance to be that guy. Asking him to be that guy as soon as next season would be on par with asking him to make the Nitto ATP Finals after just turning 19. It isn’t realistic.
But the top 10, and perhaps even Turin qualification, is not out of the question. That — along with a Grand Slam quarterfinal or even semifinal breakthrough — is what should be expected of Fonseca in 2026.