Daucik is the son of Ferdinand Daučík, the veteran La Liga manager who moved with his family to Spain in 1950.
Daucik made his La Liga debut for Real Betis on 11 September 1960 in a game against RCD Mallorca.
Yanko scored 14 goals in 38 La Liga appearances for Betis, attracting the interest of Real Madrid who signed him in 1962.
However he faced stiff competition from the likes of Alfredo Di Stéfano, Francisco Gento, Ferenc Puskás and Amancio Amaro and during two seasons at Real he only played 10 La Liga games and scored just 3 goals.
During the 1967 season Yanko played 17 games, scored 20 goals and made 8 assists for the Falcons and finished as the top scorer in the league.