U2 7643 then A3 851 at Zurich
Lisbon → Zurich → Athens
Timetable, Zurich time
13:55U2 7643 from Lisbon at the gate
11:20A3 851 to Athens leaves the gate
21 h 25 apart on the timetable, overnight
A3 851 leaves 21 h 25 after U2 7643 arrives on the timetable: more than half a day, so not a connection we count.