A teen boy and a woman punched and kicked a female straphanger during a clash that erupted after one of the assailants bumped into the victim on a Bronx subway platform, cops said Friday. 

The 42-year-old victim was waiting on the northbound Nos. 2 and 5 train platform at 149th Street–Grand Concourse around 2:40 p.m. Wednesday when another woman walked into her, police said. 

That sparked a feud that led to a beatdown – with the alleged bumper and a baby-faced male suspect repeatedly punching and kicking the victim in the face and body, authorities said. 

The woman also struck the victim in the face with a cell phone, causing pain, bruises and swelling, cops said. 

The duo – seen in clear surveillance footage released by the NYPD – fled on foot, police said. 

The victim refused medical attention at the scene. 

Cops believe that the male suspect is between 14 and 16 years old.

He was last seen wearing a black hoodie and carrying a red book bag.

The female assailant is believed to be between 30 and 35 years old, with a medium complexion, cops said.

She was last seen wearing a white T-shirt and black tight shorts.