Police are investigating after a 15-year-old girl was injured at the EFL Cup tie between Manchester City and Liverpool.
The girl was treated for head injuries at the Etihad Stadium on Thursday.
Greater Manchester Police said it was also investigating an assault on the junction of Ashton New Road and Alan Turing Way.
A man was also arrested for a racially aggravated public order offence, the force said.
A further two men were arrested on suspicion of trying to take a pyrotechnic into the ground.
Manchester City won the tie 3-2, seeing off cup holders Liverpool.