An investigation has been launched after a fan suffered a head injury following a rugby league match.
Wigan's 38-16 victory over Warrington in Thursday's Super League tie was marred by outbreaks of violence both in the stands and outside the Halliwell Jones Stadium.
Cheshire Police said officers are probing reports a 19-year-old man from Wigan suffered a cut to his head and are appealing for witnesses to come forward.
A statement said: "Cheshire Police is investigating reports of an assault that took place at the Halliwell Jones Stadium, Warrington, at approximately 10.00pm on Thursday.
"The victim, a 19-year-old man from Wigan, was leaving the Halliwell Jones Stadium at the Dallam Road end when he was hit by an unknown object which caused a small laceration to his head.
"Following the incident the victim attended Warrington District General Hospital as a precautionary measure."
An RFL spokesman said they were waiting to receive a report from ground safety officers.
Anyone with any information is asked to contact Cheshire Police on 101 quoting incident number 1050 of 9/3/2017.