EC 7154 then QR 4704 at Barcelona
Milan → Barcelona → Porto
Timetable, Barcelona time
17:25EC 7154 from Milan at the gate
08:35QR 4704 to Porto leaves the gate
15 h 10 apart on the timetable, overnight
QR 4704 leaves 15 h 10 after EC 7154 arrives on the timetable: more than half a day, so not a connection we count.