He played for the Spanish side FC Barcelona in the 1950s and 1960s, and is remembered for being a prolific striker with an excellent finishing ability.

[citation needed] He was reputed to be the creator of the "Martinez Turn", which can be seen on Movietone footage of Barcelona's quarter-final match against Wolves in the 1959–60 European Cup.

[citation needed] After leading Club Libertad to a Paraguayan League title in 1955, Martínez drew the attention of FC Barcelona who eventually signed him in 1956.

Martínez soon showcased his talent in Barcelona by leading the team in scoring in three seasons (1956–57, 1957–58, 1959–60), obtaining two Spanish League titles, two Copas del Rey and two Inter-Cities Fairs Cups.

[1][2] Martínez also became part of FC Barcelona's history by scoring the first goal ever at their current stadium, Camp Nou, on 24 September 1957.