Del Potro admires Fonseca: "He's spectacular".

João Fonseca has performed well in recent weeks to break into the top 100.

At just 18, he won the Next Gen ATP Finals in Jeddah at the end of December before playing (and winning) the first Grand Slam match of his career against top-10 member Andrey Rublev during the Australian Open.

The young Brazilian then went on to win the first ATP title of his career in Buenos Aires after dominating Francisco Cerundolo in the final.

In a press conference at the Rio tournament, Juan Martin Del Potro spoke of Fonseca's progress.

The 2009 US Open winner was effusive in his praise for Fonseca, who broke into the top 70 after his triumph in the Argentinian capital.

"I've never played the Rio Open, but the week I spent here at the 2016 Olympic Games was one of the happiest of my career.

The win over Djokovic in the first round, the semi-final against Nadal, the medal... It was all memorable. I think I've put an end to the rivalry between Argentina and Brazil. Here, I feel loved. João Fonseca can do the same thing in the other direction.

He's Brazilian, but I think people in Argentina love him for his charisma and for his tennis. He's spectacular.

What he does at such a young age, his speed, the way he hits the ball... It's incredible. I hope he can become the star that South American tennis needs.

There's no passion like what you see in Argentina, Brazil and Chile. Just look at what's happening in the Davis Cup.

Maybe having a big star like Fonseca will help in this process of public solidarity in South America," he assures us.