Marcelo Andrés Ríos Mayorga is a Chilean former professional tennis player. In 1998, he was ranked as the world No. 1 in men's singles by the Association of Tennis Professionals (ATP), becoming the first such Latin American. Ríos won 18 ATP Tour-level singles titles, including five Masters events, and was the runner-up at the 1998 Australian Open. He is the only man to have been world No. 1 in the ATP singles rankings without ever winning a major singles tournament. ATP world No. 1 from March 30, 1998 to April 26, 1998 — 4 weeks. Wiki link