it does say right here in the guide that you need to get points to rank in the top128, its not very explicit that points are what matter, but its there, and its understandable.
http://image.prntscr.com/image/05ae32d883ab45cb875e00856c1f189d.png

And you can check the points ranking right here
http://image.prntscr.com/image/c87df8c5b887440288d1af296d1a0430.png