Three football fans were arrested outside the London Stadium on Saturday as West Ham supporters' unrest threatened to boil over.
Dimitri Payet's stunning goal secured a 1-1 draw for the Hammers against Middlesbrough after four straight defeats, but there were disturbing scenes after the match as rival fans clashed outside the stadium.
Two men were arrested on suspicion of affray, and a third was held on suspicion of assaulting an officer, the Metropolitan Police said.
Stewards confirmed that police had to separate home and away supporters after clashes on the loop road through the Olympic Park.
Police escorted Middlesbrough fans away from the stadium while cordoning off some West Ham supporters.
"Only a small minority [was] intent on causing disruption,'' a police statement said.
The trouble follows earlier incidents of crowd disturbances inside the London Stadium during recent matches against Bournemouth and Watford.
Policing inside the 60,000-seat venue has been enhanced in response to ugly clashes in the opening weeks of the season.
West Ham's move from Upton Park to the former Olympic Stadium is still not sitting well with some fans, as during the game a section sang "We should have stayed at the Boleyn" and "Stratford's a s---hole, we want to go home."
Whereas Upton Park provided a formidable atmosphere, fans are separated from the pitch by the running track in their expansive, largely taxpayer-funded new home. It is only being rented from the company in charge of securing the legacy of venues from the 2012 Olympics.
West Ham vowed to crack down on those involved in violent incidents.
"West Ham United will investigate incidents involving both sets of supporters outside London Stadium after [Saturday's] 1-1 draw with Middlesbrough," the club said in a statement.
"Metropolitan Police have confirmed that two men were arrested on suspicion of affray and the third was arrested on suspicion of assaulting a police officer. All three currently remain in custody pending further enquires.
"This behaviour has no place in football and West Ham United, with cooperation from all London Stadium stakeholders, including the police, Stadium Landlords E20 and Stadium Operators LS185, will continue to operate a zero tolerance policy on such incidents.
"We must stress that the vast majority of the more than 400,000 supporters who have attended a game at the stadium since August have behaved impeccably and we will not let the acts of mindless individuals tarnish their reputation."
Information from The Associated Press and Press Association was used in this report.