The Croatian centre-back helped Steven Gerrard’s men complete a two-legged victory over the Slovenian side on Thursday evening as an inspired performance from keeper Allan McGregor enabled the Light Blues to protect their 3-1 first-leg advantage.
They now face a showdown with Russian side Ufa for a spot in the group stages.
After the match, Katic posted a video to his Instragram story showing Rangers fans on the fencing outside the ground as they sang his name.
In the post he wrote “f***ing best fans in the world”.
The 21-year-old was a summer signing from Slaven Belupo and has already proven to be a big hit with fans as he’s formed a robust partnership with fellow new recruit Connor Goldson at the heart of the defence.