An unsuspecting straphanger was sucker-punched in a random attack while walking on a subway platform, a wild new video shows.

The violence broke out just before midnight Sunday as the 27-year-old was looking down at her phone while walking inside the  Clinton-Washington Avenues subway station, according to cops and the video.

The unknown attacker appears in the video to be exchanging words with a couple on the platform before turning around and walking toward the woman.

“I should be paying more attention, but ya know,” the victim, Matilda, posted on TikTok.

The man then jogs toward the woman and clocks her in the left eye, sending her to the ground.

“There I go,” she says as she falls while narrating the surveillance footage.

“People come out to help me, but it does show his face clearly, so I’m hoping they are able to catch him,” the woman says in the video, where she can be seen with a black eye.

Cops said the suspect ran off in an unknown direction after exiting the station.

She did not receive medical attention.