Mary Murphy -- My Manager Screwed Me Royally

Mary Murphy is convinced ... her former manager is now accusing her of being a coke-head and a nympho because she fired him and sued him for allegedly stealing $60,000 from her ... sources with knowledge of the situation tell TMZ.

As we reported, Michael Sanchez sued Murphy Monday for commissions, and in the lawsuit he alleged a panoply of misdeeds on Murphy's part, including claims that she was wasted on the set of "So You Think You Can Dance," snorted cocaine, slept with a producer and illegally coached contestants.

But sources connected with Murphy tell us ... they believe Sanchez is trying to embarrass Murphy on the eve of the show's Thursday premiere because she has sued him for double-dealing her over a show she was in -- "Burn the Floor."

According to the suit, filed in December, Murphy says Sanchez secretly went to producers of the play and told them not to pay Murphy directly, but rather to put the $60,000 in his account and then he would take care of her. Murphy says Sanchez didn't give her a penny.

Murphy's lawsuit has been put on hold because Sanchez has filed for bankruptcy. She's listed as a creditor.