After exceptional performances he transferred to Associação Desportiva São Caetano where he then left for Sport Club Corinthians Paulista.
At Corinthians, Marcelo established himself where he excelled alongside Carlos Tevez and Javier Mascherano being dubbed the team of the year after the trio won the Championship.
He was part of the Brazilian team that played at the FIFA U-17 World Championship 2001.
Marcelo Mattos has signed for Greek team Panathinaikos for 3 million euros on 6 July 2007 in a 4-year deal.
[2] In July 2008, Panathinaikos acquired the 85% of the players ownership for a fee of 3 million Euros.