UA 2806 then DL 9963 at Atlanta
Denver → Atlanta → Queretaro
Timetable, Atlanta time
15:12UA 2806 from Denver at the gate
09:30DL 9963 to Queretaro leaves the gate
18 h 18 apart on the timetable, overnight
DL 9963 leaves 18 h 18 after UA 2806 arrives on the timetable: more than half a day, so not a connection we count.