DL 3122 then DL 589 at Atlanta
Pittsburgh → Atlanta → Mexico City
Timetable, Atlanta time
22:00DL 3122 from Pittsburgh at the gate
19:57DL 589 to Mexico City leaves the gate
21 h 57 apart on the timetable, overnight
DL 589 leaves 21 h 57 after DL 3122 arrives on the timetable: more than half a day, so not a connection we count.