IB 631 then U2 6842 at Zurich
Madrid → Zurich → Porto
Timetable, Zurich time
18:55IB 631 from Madrid at the gate
16:50U2 6842 to Porto leaves the gate
21 h 55 apart on the timetable, overnight
U2 6842 leaves 21 h 55 after IB 631 arrives on the timetable: more than half a day, so not a connection we count.