The thing is, those two hooligan groups are rivals and he placed a scarf of Rad hooligans on the woodwork. Zemun hooligans came in, took the scarf, he ran towards them to get it back and they beat him.

Kudos to him for being brave to fight a bunch of them but all of that was madness.

In addition to that, a Rad hooligans leader invaded the pitch to try to defend him but police took him and beat severely. No action against Zemun hooligans though.