Marcos Diniz Daniel (born on July 4, 1978 in Passo Fundo, Rio Grande do Sul) is a professional tennis player from Brazil who turned professional in 1997. The right-hander reached his highest singles ATP-ranking on September 14, 2009, when he became World No. 56. He is coached by his brother, Márcio.
Marcos Daniel's brother owns an academy for developing young tennis players, called Daniel Tennis Center where Marcos Daniel used to work as a ball catcher. He started playing youth tournaments at age 5. When he was 12, representing this academy, he reached his first final but he did not succeed in winning the title.
In August 2009, he reached the semi-finals of the ATP Gstaad tournament. He also reached the semi-finals there in 2006.