A3 710 then FR 4545 at Barcelona
Athens → Barcelona → Porto
Timetable, Barcelona time
10:25A3 710 from Athens at the gate
06:45FR 4545 to Porto leaves the gate
20 h 20 apart on the timetable, overnight
FR 4545 leaves 20 h 20 after A3 710 arrives on the timetable: more than half a day, so not a connection we count.