Police say it happened just before 5 p.m. on a southbound E train after an argument.
The suspect reportedly stepped on the foot of the 25-year-old. Police say she then spat on him, and he punched her in the face. The woman then stabbed the man with a sharp object.
The suspect, described as a black woman with blue hair wearing a black bubble jacket, fled the scene.
The victim was rushed to Bellevue Hospital with non-life threatening injuries.
----------
* More Manhattan news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube