Expect mellifluously alliterative outrage from Al Sharpton after this “slip of the tongue”:

City Councilman David Yassky, locked in a racially charged congressional race, was all smiles yesterday as Mayor Bloomberg introduced him as “Congressman Yassky.”

Speaking at the first groundbreaking to come from last year’s Williamsburg-Greenpoint re-zoning, the mayor praised Yassky — but press secretary Stu Loeser insisted there was no endorsement, just “a slip of the tongue.”