Marcos Diniz Daniel (born July 4, 1978, in Passo Fundo, Rio Grande do Sul) is a retired professional tennis player from Brazil who turned professional in 1997.

The right-hander reached his highest ATP singles ranking of World No.

When he was 12, representing this academy, he reached his first final but he did not succeed in winning the title.

[1] In August 2009, he reached the semi-finals of the ATP Gstaad tournament.

He qualified for the 2009 French Open and lost in the first round to Rafael Nadal after giving a strong performance, 5–7, 4–6, 3–6.