A man was slashed early Thursday after an argument with two foes on the Upper West Side, cops said.

The victim, whose age wasn’t immediately known, was on West 73rd Street and Amsterdam Avenue just after 3 a.m. when he got into a fight with the two men, police said.

One of them pulled out a blade and started to slash him in the back and shoulder repeatedly, sources said.

The man was rushed to St.Luke’s Hospital where he is expected to survive, according to authorities.

Police are still searching for the duo, and described the slasher as a skinny man, standing 5-foot-9, with a hooded sweatshirt and dark pants.

A description of his pal wasn’t readily available.

It wasn’t immediately clear what they were arguing about.