F9 45 then G7 3376 at O'Hare
Cancún → Chicago → St Louis
Timetable, Chicago time
14:45F9 45 from Cancún at the gate
11:00G7 3376 to St Louis leaves the gate
20 h 15 apart on the timetable, overnight
G7 3376 leaves 20 h 15 after F9 45 arrives on the timetable: more than half a day, so not a connection we count.