Joao Fonseca became the youngest Brazilian to win an ATP tournament on Sunday after the 18-year-old captured the Argentina Open title with a 6-4, 7-6(1) win over home favourite Francisco Cerundolo.
Fonseca has established himself as one of the game's most exciting young talents with his victory at the ATP Next Gen Finals in Jeddah in December and his win over ninth seed Andrey Rublev in the first round of the Australian Open last month.
He lost to Italy's Lorenzo Sonego in five sets in the second round at Melbourne Park.
"It is a dream, I work every day for these moments. Playing a final away from home, in Argentina, is difficult," said Fonseca after denying fifth seed Cerundolo the title in front of a raucous crowd in Buenos Aires.
"It's very special and I've taken another step forward in my career and I'm closer to my dream of becoming world number one," he told a press conference.
Fonseca also defeated Argentines Tomas Martin Etcheverry, Federico Coria and Mariano Navone in the earlier rounds before beating Serbian Laslo Djere in the last four.
Cerundolo had stunned top seed Alexander Zverev of Germany in the quarter-finals before knocking out Spain's Pedro Martinez in the semis.