UA 751 then UA 3636 at O'Hare
Charlotte → Chicago → Knoxville
Timetable, Chicago time
07:25UA 751 from Charlotte at the gate
07:07UA 3636 to Knoxville leaves the gate
23 h 42 apart on the timetable, overnight
UA 3636 leaves 23 h 42 after UA 751 arrives on the timetable: more than half a day, so not a connection we count.