Joao Fonseca & On are proving to be powerful doubles partners in tennis

Joao Fonseca is making history on the court while wearing On tennis shoes and apparel.

Joao Fonseca of Brazil with the trophy after his men's singles final win over Francisco Cerundolo at IEB+ Argentina Open 2025. / IMAGO / NurPhoto

Tennis fans who do not yet know much about Joao Fonseca need to tune in because he is shaking up the sport at just 18 years old. Fonseca has a magnetic personality, and young fans want to be like him (which includes his fire on-court kits).

Fonseca is one of the rising stars on the Swiss sportswear brand On's roster of tennis players. Over the past two months, Fonseca has joined Iga Swiatek and Ben Shelton in wearing the brand's pink, yellow, and white kits (we lovingly refer to as the "Creamsicle" colorways.

Fonseca just ended a dream week at the Argentina Open by defeating home-town hero Francisco Cerundolo, 6-4, 7-6 to capture his first-ever ATP Tour Title. On is touting Fonseca's incredible achievement and helping elevate him to new heights in the sportswear world.

Joao Fonseca in the Argentina Open. / IMAGO / NurPhoto

Players and fans can dress like Fonseca by visiting the On website, where on-court kits and shoes are available.

Playing in his first-ever ATP Tour final, Fonseca had the backing of an energized crowd, who were mesmerized by the Brazilian's talent and shots. Trading breaks in the first two games, it was a scratchy beginning before Fonseca settled in, winning another break and ultimately pocketing the first set 6-4.

In the second set, Fonseca broke again to lead 3-2 and extended his lead to 5-3, but Cerundolo had other plans, playing his way back into the match and forcing a tie-break. Fonseca stormed through the tie-break, winning it 7-1 and celebrating his first ATP Tour Title.

Joao Fonseca in the Argentina Open. / IMAGO / NurPhoto

Simultaneously, he also became the first man born in 2006 or later to in an ATP Tour title and the youngest Brazilian to win an ATP title in the Open Era. He is also the fourth-youngest player from anywhere to win an ATP title this century.

On his way to the final, Fonseca, who has now become the lowest-ranked champion ever in the Argentina Open history, beating T. Etcheverry (44) 6-3, 6-3, F. Coria (115) 2-6, 6-4, 6-2, M. Navone (47) 3-6, 6-4, 7-5 and L. Djere (112) 7-6, 5-7, 6-1.

Speaking about the support in his on-court interview, Fonseca said: "Even in Argentina, there are Brazilians cheering for me. That's amazing. What I'm living is just unbelievable. I want to thank my friends and sponsors for helping me achieve my dream - to just play tennis."

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