Things got physical on a Manhattan subway Friday when two straphangers came to blows over elbow room, cops said.

Tempers rose when a young woman boarded a northbound 6 train at 68th Street Station around 2:20 pm and took up too much space next to a 70-year-old rider, officials said.

The older woman moved to a different seat after she was elbowed several times, but a confrontation erupted anyway, with nasty talk quickly escalating as the younger woman slapped the septuagenarian.

The victim fought back, kicking and jabbing at her attacker before she was slapped again, said police.

The younger woman fled from the train at the 86th Street Station. The victim exited at the 96th Street Station and reported the incident. She was treated on scene for pain and swelling.