A3 621 then GQ 840 at Athens
Brussels → Athens → Vienna
Timetable, Athens time
15:25A3 621 from Brussels at the gate
11:40GQ 840 to Vienna leaves the gate
20 h 15 apart on the timetable, overnight
GQ 840 leaves 20 h 15 after A3 621 arrives on the timetable: more than half a day, so not a connection we count.