Shaq -- RIPS SCOTTIE PIPPEN ... You Were MJ's Bitch

Shaq just opened fire on Scottie Pippen -- saying he can't talk smack when it comes to championships because all he did was ride Michael Jordan's coattails.

It all started when Shaq posted a pic of the 5 greatest Bulls of all time (including Pippen) ... and the 5 greatest Lakers of all time (including Shaq) and said the Lake Show would crush CHI by 50!!

Pippen responded with a pic of him and MJ after winning a title and said, "Sorry @shaq but I don't get caught up in hypotheticals. All I know is we won 6 titles, twice the amount you claimed while in LA.."

That's when Shaq hit back -- replacing Pippen's face in the original shot with MJ's face and writing, "Sorry @scottiepippen I don't believe in hypotheticals either, but I seen most of those final you did ok, but this guy did most the work."

And he didn't stop there -- "#youwereok steve kerr and Ron harper deserve more credit than you , remember I WAS BATMAN YOU WAS ROBIN , I was PUFFY YOU WAS MASE."

Stay tuned -- this probably ain't over yet!!