Joao Fonseca said a change in mentality and months of hard work have helped fuel his rise to a first Grand Slam quarter-final after the Brazilian teenager's breakthrough run at the French Open.
The 19-year-old reached the last eight of a major for the first time on Sunday with a 7-5 7-6(8) 5-7 6-2 victory over two-time runner-up Casper Ruud.
"Pre-season in December was pretty tough," he told reporters. "Australia can be an example, because I was with no rhythm at all. Practiced like two days with 13 days off and tried to play.
"But what changed is doing a lot of physical stuff and working hard."
After winning the 2024 Next Gen ATP Finals, Fonseca burst into the spotlight with an upset of Andrey Rublev at the 2025 Australian Open.
He said his experiences over the past year had helped shape his progress.
"The mentality also changed a lot, focusing on the points and not in the end of the match," he said.
"I'm out of home since Monte-Carlo, but I think a lot of work came. Mentality improved a lot."
Fonseca said he felt more comfortable imposing himself against Ruud than he had during his earlier victory over Novak Djokovic in Paris, repeatedly taking the initiative against one of the circuit's strongest clay-court players.
"Against Djokovic was more mental," he said.
"I was feeling more confident in today's match and more aggressive, going for the shots and trying to command on the points pretty soon."
Three-times champion Gustavo Kuerten watched Sunday's match from the stands and Fonseca enjoyed having the support of his countryman.
"Having Guga there supporting and cheering was amazing and super-nice experience today," he added.
"It's different. Of course my first time, but just living the moment."
