He is the assistant manager of both FC Rostov in the Russian Premier League and the Russia national team.

As a player, Onopko held the record for most international appearances for the Russia national team until 2015.

During that time, he played for Shakhtar Donetsk, Spartak Moscow, Real Oviedo, Rayo Vallecano, Alania Vladikavkaz and Saturn Ramenskoye.

On 26 July 2021, he was hired as an assistant to Valeri Karpin in the Russia national team.

[3] In February 2022, after FIFA and UEFA suspended Russian clubs and the national teams from international competitions amidst the Russian invasion of Ukraine, Karpin returned as manager to FC Rostov and hired Onopko as his assistant there as well.