Kei Nishikori
He began tennis when he was five years old. He has achieved a national Triple Crown at 11 years old and he was trained in the United States from 13 years old. He turned professional when he was 17 years old and he won his first professional tournament at 18 years old. He injured his elbow in 2009, but he returned the following year. As of August 2015, he is ranked number 4 in the world.