Isaka Aongor Čerňák-Okanya (born 9 April 1989) is an Australian professional footballer who plays as an attacking midfielder for Olympic FC.

[3] During the 2010–11 season Melbourne Victory signed Cernak for the following season and Asian Champions League campaign as a replacement for departing striker Robbie Kruse to Bundesliga 2 club Fortuna Düsseldorf, with Fury unable to extend his contract due to FFA ownership of the club.

Isaka stated upon signing: "Being able to have one-and-a-half years to learn as a footballer off 'Mossy' (Phil Moss) and the players at Central Coast Mariners is really exciting for me.

[7] However, Isaka struggled to make an impact and made just 7 league appearances before he sustained a knee injury that required surgery, ruling him out for the rest of the season.

[9] His signing for Singapore Premier League side Home United was announced on 13 July 2018, coming in to fill the vacant slot for foreign players left by Sirina Camara (whose season had been prematurely cut short by an ACL injury).