UA 3851 then DL 643 at San Francisco
Rio De Janeiro → San Francisco → New York JFK
Timetable, San Francisco time
17:41UA 3851 from Rio De Janeiro at the gate
14:05DL 643 to New York JFK leaves the gatealso AF 2593, LY 4568, VS 4844, LA 6672
20 h 24 apart on the timetable, overnight
DL 643 leaves 20 h 24 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.