UA 489 then DL 3876 at Denver
Santa Ana → Denver → Austin
Timetable, Denver time
12:06UA 489 from Santa Ana at the gate
09:42DL 3876 to Austin leaves the gate
21 h 36 apart on the timetable, overnight
DL 3876 leaves 21 h 36 after UA 489 arrives on the timetable: more than half a day, so not a connection we count.