CHICAGO (CBS) — A man stabbed an assailant who was attacking him early Tuesday at the Sedgwick Brown Line station on the city’s Near North Side, police said.

At 6:47 a.m., the 45-year-old man was entering the turnstile at the station on Sedgwick Street just below North Avenue when another man, 46, followed him in and began physically attacking him, police said.

The assailant at one point hit the victim with a cone, police said.

The victim eventually stabbed the assailant in the upper chest, police said.

The assailant was taken to Northwestern Memorial Hospital in good condition, police said. The victim was not injured.

Police said the stabbing was deemed to have been in self-defense. Charges against the assailant who was stabbed were unknown Tuesday afternoon, and Area Three detectives were processing the case.