OS 806 then FR 751 at Vienna
Athens → Vienna → Porto
Timetable, Vienna time
09:15OS 806 from Athens at the gate
07:40FR 751 to Porto leaves the gate
22 h 25 apart on the timetable, overnight
FR 751 leaves 22 h 25 after OS 806 arrives on the timetable: more than half a day, so not a connection we count.