The shocking footage shows a man jogging up behind the 16-year-old and hitting her around the head.
The girl was left lying on the ground in Plaistow, east London, as her attacker casually jogged off.
A Scotland Yard spokesman said: “A man, aged 34, was arrested yesterday evening in connection with the assault of a 16-year-old female in High Street, Plaistow.
“He remains in custody at an east London police station.”
The teenager is now recovering after the attack which happened outside the Black Lion pub at around 12.30pm on November 13.
The girl, who needed work on her teeth following the assault, is said to be “bearing up really well”.[media id=723 width=610 height=340]