Brian McKnight is already declaring a victory in his defamation case against ex-wife Julie McKnight ... after she didn't appear in court.

Brian filed a motion for default judgment, and is waiting for the court to sign off to make his win official ... but that technicality didn't prevent Brian from celebrating. Getty

The R&B legend posted a video of himself smoking a cigar, saying, "The verdict is in" -- it isn't -- "according to the courts, trying to ruin my name and trying to bring harm to my family in a book filled with lies equals $8.8 million."

The suit alleges Julie made false claims about Brian in her book, "Mama Bear: Beautifully Blended," basically calling him an abusive husband and neglectful father to their children.

The gleeful video continues with Brian running aroun

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