Just be careful if you are the mooring for an extended period of time or if conditions deteriorate. When on the mooring for extended periods it is best to have a special mooring rig made. It consists of a swivel shackle and usually two mooring lines. The lines have thimbles spliced into the eyes, which are permanently spliced onto the shackle. The shackle is than attached to the mooring ball with a large clevis pin.
Like I said, short periods of time are ok, but any length of time or heavy weather and the simple line through the ball will chafe and break. Overnight in calm conditions, you’ll be just fine.