 Mateianu was one of the finest playmakers of Romanian football during the 1960s, and was also noted for fair play during matches.After playing for Flacăra Boldești and then Progresul București as a youth, Mateianu made his debut at the senior level in 1957, aged 19, when he was enrolled in Progresul's first squad.After just one year he signed to Știința Cluj, returning to Progresul in 1963.