Aston Villa won the match, which took place at Villa Park, 4-2
Four men have been arrested following violence and disorder at the match between Aston Villa and Birmingham City on Sunday, police said.
One, aged 42, from Birmingham, was arrested on suspicion of sexual assault against a woman leaving the game at Villa Park.
Another, aged 22, was arrested after allegedly setting off a flare inside the stadium, West Midlands Police said.
A 25-year-old from Birmingham was arrested on suspicion of affray and possessing class A drugs, while a 19-year-old, also from Birmingham, was arrested on suspicion of possessing Class A drugs.
5:04 Highlights from the Second City derby as Aston Villa hosted rivals Birmingham at Villa Park in the Sky Bet Championship Highlights from the Second City derby as Aston Villa hosted rivals Birmingham at Villa Park in the Sky Bet Championship
“Small pockets of violence were reported before and after the match,” the force said, but officers were “quick to restore calm”.
Superintendent Phil Dolby said: “Fortunately, the four men arrested don’t represent the majority of fans who enjoyed a great game in the way you’d expect.
“There was a large operation in place for the match which involved us working closely with both clubs and their respective supporter associations.
“Our officers will remain in the area and city centre in the hours after the game to keep everyone safe.”
The Championship game was won by Aston Villa 4-2.