A Bronx man was arrested Friday for viciously assaulting a teenage girl he had just met on a subway platform, cops said.

Shaun Lewis, 27, allegedly convinced the 15-year-old to walk with him from the Gun Hill Road subway station to Bronx Park just before 5 a.m. Monday.

In the park, he beat, choked and tried to rape her — leaving her with a serious head injury — before fleeing, cops said.