AC 1039 then DL 3876 at Denver
Toronto → Denver → Austin
Timetable, Denver time
10:35AC 1039 from Toronto at the gate
09:42DL 3876 to Austin leaves the gate
23 h 07 apart on the timetable, overnight
DL 3876 leaves 23 h 07 after AC 1039 arrives on the timetable: more than half a day, so not a connection we count.