Nicolás Alejandro Massú Fried, nicknamed El Vampiro, is a Chilean former professional tennis player and a coach. A former world No. 9 in singles, he won the singles and doubles gold medals at the 2004 Athens Olympics. He is the only man to have won both gold medals at the same Games since the re-introduction of Olympic tennis in 1988, and they are Chile's only two Olympic gold medals. Massú also reached the final of the 2003 Madrid Masters and won six singles titles. He was the coach of 2020 US Open champion and former world No. 3 Dominic Thiem from 2019 to 2023.

Tennis was part of the Summer Olympic Games program from the inaugural 1896 Summer Olympics, but was dropped after the 1924 Summer Olympics due to disputes between the International Lawn Tennis Federation and the International Olympic Committee over how to define amateur players. After two appearances as a demonstration sport in 1968 and 1984, it returned as a full medal sport at the 1988 Summer Olympics open for all players regardless of their age and status and has been played at every summer Games since then.