That negative run differential is fast disappearing! After losses in the first 2 games of August, the differential was, if I have figured right, -62. Now it is -14, meaning +48 since early August (and +25 just in September). No wonder they are winning. And -- for the month of September they are leading the majors in runs scored!! Of course scoring 19 the last two games helped. No wonder they are winning.
There have been two ways to look at the negative run differential. One was that it was a millstone that would drag them down -- eventually they would start losing all the games that they did not lose earlier. The other was that it is a gift -- they have all these "extra" wins in hand to build on. Happily the second one seems to be playing out, thanks to much better play in the late-season.