Buenos Aires, Feb. 17 -- Brazilian teenager Joao Fonseca secured his first ATP tour title beating local favorite Francisco Cerundolo 6-4, 7-6(1) in the Argentina Open final.

The 18-year-old showed composure beyond his years, winning 73% of his first-serve points to prevail in an hour and 45 minutes on the outdoor clay of the Buenos Aires Lawn Tennis Club on Sunday.

"Unbelievable week, even in Argentina there are some Brazilians cheering for me," said an emotional Fonseca.

"It's just amazing. Every Brazilian, everyone from their country wants this support from your own country. For me, this [moment] that I'm living is just unbelievable."

Fonseca became the 10th youngest title winner and the youngest South American champion since the ...