At the 1994 World Junior Championships, he advanced to the semi-finals of the 400 m hurdles by finishing third in his heat.
He placed sixth in his semi-final, running slower and failing to advance to the finals by 0.45 seconds.
[2] Holúbek later competed at the 1998 European Championships, the 1999 Military World Games and the 2000 Summer Olympics without reaching the final.
[1][3] At the European Cup, Holúbek mainly competed for Slovakia in the Second League.
[3] Domestically, he was a three-time Slovak Athletic Federation outdoor champion in the hurdles, as well as the 1995 indoor champion in the flat 400 m.[5][6] His personal best time was 50.18 seconds, achieved in July 2000 in Budapest.