FR 9754 then OS 823 at Vienna
Banja Luka → Vienna → Thessaloniki
Timetable, Vienna time
14:30FR 9754 from Banja Luka at the gate
12:30OS 823 to Thessaloniki leaves the gate
22 h apart on the timetable, overnight
OS 823 leaves 22 h after FR 9754 arrives on the timetable: more than half a day, so not a connection we count.