Multiple choice general knowledge Juan Martín del Potro defeated Roger Federer in the US Open. He belongs to Brazil Argentina France Spain Reveal answer Fill a bubble to check yourself B Correct answer Explanation Juan Martín del Potro is a famous tennis player from Argentina who defeated Roger Federer in the 2009 US Open final. He is known for his powerful forehand and won the US Open that year. Brazil, France, and Spain are incorrect.