Score one for Mayor Bloomberg.

Retired Manhattan DA Robert Morgenthau yesterday abruptly resigned as overseer of the court-ordered effort to recruit more minorities to the city’s Fire Department.

The move came after arch-enemy Bloomberg had ordered city lawyers to protest the longtime prosecutor’s appointment last week, claiming that Morgenthau was biased against his administration because of past clashes.

“This contention [of prejudice] is absurd,” an obviously furious Morgenthau wrote yesterday to Brooklyn federal Judge Nicholas Garaufis, who had appointed the ex-DA special master of the recruitment issue.

Garaufis named ex-US Attorney Mary Jo White to replace Morgenthau.

But he clearly wasn’t happy with the city.

“This appointment [of Morgenthau] was necessitated by the city’s refusal to obey court orders to fulfill its remedial-phase obligations in a timely manner,” Garaufis wrote in a scathing response.

“The city has now decided to further delay proceedings by attempting to disqualify the very person who was appointed to speed things up.”