IB 550 then CX 1751 at Madrid
Porto → Madrid → Buenos Aires
Timetable, Madrid time
23:00IB 550 from Porto at the gatealso LA 1678, VY 5311, QR 6526, BA 7124
12:20CX 1751 to Buenos Aires leaves the gatealso BA 4255, AY 5375
13 h 20 apart on the timetable, overnight
CX 1751 leaves 13 h 20 after IB 550 arrives on the timetable: more than half a day, so not a connection we count.