STUTTGART Unseeded Argentine teenager Juan Martin del Potro upset French second seed Richard Gasquet 6-4 7-5 to win the Stuttgart Cup claycourt event on Sunday.
The towering 1.95-metre tall world number 65 benefited from some erratic play by the French number one to deservedly clinch his first ATP title.
"I always dreamed as a young boy of winning a tournament, and now I've done it it's just unbelievable," Del Potro, 19, said in an on-court interview.
"I knew I had to serve well to win, and now I can just enjoy it."
Del Potro showed resilience and steady nerves in both sets.
After breaking Gasquet early on in each, he was pulled back to level terms in the subsequent games.
Rather than folding, he responded with further decisive breaks against the world number 15 in the penultimate game of each set, serving out to love at the end of the second to wrap up his win.
"For sure I want to congratulate him on his first title," said Gasquet, a former world number seven who has gone 10 months since winning his fifth career title in Mumbai last September.
"I remember winning my first title and it's an important step. I would say he has all it takes to make it into the top five."
(Writing by Mark Ledsom in Berne, editing by Justin Palmer)