AC 4121 then UA 871 at San Francisco
Ontario → San Francisco → Taipei
Timetable, San Francisco time
17:50AC 4121 from Ontario at the gate
13:35UA 871 to Taipei leaves the gate
19 h 45 apart on the timetable, overnight
UA 871 leaves 19 h 45 after AC 4121 arrives on the timetable: more than half a day, so not a connection we count.