Nicolás Alejandro Massú Fried (born October 10 1979), nicknamed Vampiro (Spanish for vampire) is a tennis player from Chile.

Massú was born in Viña del Mar, Chile. His mother, Sonia Fried, is of Jewish descent, and his father, Manuel Massú, of Palestinian ancestry. His Hungarian grandfather, Ladislao Fried, introduced him to the sport at age 5.

From age 12, Massú was trained by Leonardo Zuleta, with whom he perfected his forehand and double-handed backhand . He became a professional tennis player in 1997.

Massú represented Chile at the Sydney 2000 Summer Olympic Games in Australia, and was the country's standard bearer at the games's opening ceremony .

In late 2003, Massú reached the final at the Madrid Tennis Master Series tournament, losing to Spaniard Juan Carlos Ferrero.

He reached his best ATP Singles Ranking position in 2004, holding the 9th spot.

In mid-2004, Massú parted ways with Argentinian coach Gabriel Markus ; he was replaced by compatriot Patricio Rodríguez . Later that year, at the Olympic Games in Athens, he and doubles partner Fernando González gave their country its first ever Olympic gold medal, when they defeated Nicolas Kiefer and Rainer Schüttler of Germany to win the men's doubles tournament. The next day, he captured his second gold medal by defeating American Mardy Fish in five sets in the men's singles final.

Trivia

• Chosen as Athlete of the Day on August 23 by the 2004 Athens Olympics' official web site, following his victory in singles.