A3 961 then A3 780 at Athens
Bucharest → Athens → Zagreb
Timetable, Athens time
11:50A3 961 from Bucharest at the gate
07:35A3 780 to Zagreb leaves the gate
19 h 45 apart on the timetable, overnight
A3 780 leaves 19 h 45 after A3 961 arrives on the timetable: more than half a day, so not a connection we count.