Kelly (10-5) allowed three hits and struck out five.
They now go on to host the National League Divisional Series against the winner of Tuesday's NL Wild Card between Pittsburgh and Cincinnati.
Cubs starter Jeff Samardzija (8-13) took the loss, yielding three runs on eight hits over six innings.
Chicago (66-96) ended with six losses in seven games.
Couple calls 9-1-1 over missing hash browns; assault McDonanld's employees
Workers accuse National Zoo of animal mismanagement