Juan "Jack" Diego Nelson y Duggan (May 26, 1891 – August 7, 1985 in Buenos Aires, Argentina) was an Argentinepolo player. He competed in the 1924 Summer Olympics, and was part of the Argentine polo team which won the gold medal. In 1936 he was once again part of the team but didn't take part of any game, nevertheless he won a second gold medal being the first Argentine to achieve that.[1] In 2008, Javier Mascherano became the second Argentine to win two olympic gold medals.
