UA 320 then UA 3755 at Houston
Denver → Houston → Lubbock
Timetable, Houston time
08:33UA 320 from Denver at the gate
22:10UA 3755 to Lubbock leaves the gate
13 h 37 apart on the timetable
UA 3755 leaves 13 h 37 after UA 320 arrives on the timetable: more than half a day, so not a connection we count.