Scott Disick -- Pulls Out of Las Vegas Club Gig

Scott Disick is saying NO to partying his face off -- for at least one night -- he's backed out of a paid hosting gig in Las Vegas.

Disick just made the 11th hour decision to postpone his Friday night appearance at 1Oak Nightclub in Vegas.

The decision comes on the heels of Kourtney Kardashian pulling the plug on their relationship -- and after Scott missed their 3-year-old daughter Penelope's birthday this week.

We broke the story ... Disick's friends had been urging him to cancel on 1Oak, and get into rehab.