Sergio Ismael Díaz Velázquez is a Paraguayan professional footballer who plays as a forward for Greek Super League club Panetolikos.

Panetolikos Football Club, or with its full name Panetolikós Yimnastikós Filekpedeftikós Síllogos, is a Greek professional football club. It was based in Agrinio, Greece. Panetolikos was founded in 1926 and is considered one of the historical clubs in Greece, currently participating in the Greek First Division. Some of the most well known players that started their career in the club are Stratos Apostolakis, former Greek recordman in international caps (96), and Petros Michos.