MTA worker punched trying to break up platform fight near scene of Brooklyn slaying

A Metropolitan Transit Agency worker was punched in the face after stepping in to break up a subway argument Thursday — just steps from where a sword-wielding wacko murdered an innocent man the week before, cops said.

MTA track worker Michael Grosso, 59, was on duty a little after midnight, working on the southbound A/C line in the Jay Street station, when he spotted a man arguing with a passenger on the platform and decided to step in, police sources told The Post.

However, Grosso quickly became the next target.

The suspect — who police described as a black male in his 40s dressed in all black — turned on Grosso, balling up his fist and punching Grosso in the left side of the face, police said.

The suspect then bolted topside escaping into the night.

Despite the shocking attack, the MTA worker refused medical attention at the scene.

The location of the Jay Street subway is where a beloved Brooklyn security guard was senselessly murdered in a nearby corridor days earlier.

Nicola Tanzi, 64, was brutally beaten and stomped to death after he held the subway security gate open for David Mazariegos, 25.

Mazariegos was arrested a few hours later in Times Square toting a samurai sword — a bizarre detail that has stunned New Yorkers.

The maniac told police he didn’t like the way Tanzi looked at him.

The Post reached out to a spokesperson at the Transit Workers Union about Thursday’s attack but did not immediately receive a response.