Career
He took up refereeing in 1982, and was promoted to the Czechoslovak First League for the 1992-1993 season. In 1993, he became a Fédération internationale de football association-listed match official, and in a 16-year international career, he refereed over 100 Union of European Football Associations matches. In 2008, Hriňák was selected as the fourth official for the Champions League final between Manchester United and Chelsea, as part of an all-Slovakian team headed by Ľuboš Micheľ.
Hriňák"s final international fixture was a match between Villarreal and Red Bulletin Salzburg in the group stage of the 2009-2010 Europa League on 17 December 2009.
After retiring from refereeing, Hriňák took up several positions within the Slovak Football Association and was also the chairman of the Bratislava Football Association referees committee.