Rising Brazilian star Joao Fonseca has acknowledged mounting pressure and ongoing physical challenges following an early defeat at the Argentina Open, one year after lifting his first ATP title at the same venue.
Returning to Buenos Aires as defending champion and third seed, Fonseca was eliminated by Alejandro Tabilo in a closely fought three-set match, losing 6-3, 3-6, 7-5. The result marked his third consecutive defeat and underlined a difficult start to the 2026 season.
Speaking after the match, Fonseca admitted that expectations had affected his performance. He said he felt tense from the opening games and struggled to find confidence despite trying to draw energy from the crowd. He also pointed to physical discomfort, explaining that his body was preventing him from playing the shots he wanted.
The 18-year-old has been dealing with persistent lower back problems since late last year. The issue forced him to withdraw from warm-up tournaments in Brisbane and Adelaide and contributed to his first-round exit at the Australian Open.
His team has confirmed that he is managing lumbar hypolordosis, commonly known as flatback syndrome, a condition in which the lower spine loses its natural curve. The problem can restrict movement, reduce flexibility, and cause chronic pain, making it especially challenging for professional athletes who rely on explosive movement and endurance.
Fonseca has previously revealed that he was born with a back condition and suffered a stress fracture five years ago. He said the pain varies from day to day and is something he must manage throughout his career. His support team has stressed the importance of a long-term approach, prioritising health over short-term results.
Despite recent setbacks, Fonseca remains focused on his development. With the Buenos Aires tournament over, he is now preparing for the Rio Open, where he will compete on home soil from February 16 to 22.
The event is expected to feature strong competition, including Francisco Cerundolo, Matteo Berrettini, and Gael Monfils.
Fonseca has also played down comparisons with Brazilian legend Gustavo Kuerten and modern star Carlos Alcaraz, insisting he is focused on building his own path.
He said his priority is to improve his mental strength and physical conditioning while progressing at his own pace. As he looks ahead to Rio, Fonseca will be hoping that home support and improved fitness can help him regain momentum and reaffirm his long-term potential on the ATP Tour.
