Sunderland fans had to run a gauntlet of threats and intimidation as they left the London Stadium after their last-gasp 1-0 defeat yesterday by West Ham United, it has been claimed.
Posts on social media have reported that small groups of visiting fans - even young and the elderly - were singled out by a hardcore of home supporters intent on trouble at the 60,000-capacity stadium.
One fan posted on the Ready To Go (RTG) Sunderland fans' forum: "For the first time in what seems years I felt afraid today. The stewards outside the ground after the game did not seem to know what they were doing.
"At one point myself and other Sunderland supporters were pushed towards West Ham fans who were lashing out at us, and it was the intervention of the police who stopped it getting any worse."
Spectator safety in the ground - the former Olympic Stadium - is looked after by stewards rather than the Metropolitan Police, and trouble has been reported at several games already this season.
A West Ham fan posted some mobile phone footage on social media sites which appeared to show Sunderland fans running up a grass bank to confront home supporters after the match, as they returned to where the away coaches were parked.
But a Sunderland fan who was there replied: "I was right next to where that happened. It was in reaction to a group of ******* standing at the top goading Sunderland fans, arms outstretched, inviting trouble.
"They sharp ran off when the lads ran up the hill. Let's be clear, this wasn't a group of Sunderland fans running up attacking innocents. The idiots at the top were inviting trouble. Rightly or wrongly, they got what they wanted."
Another agreed, saying: "We were outside the ground and people were getting sick of being constantly confronted, surrounded and goaded by them. With frustrations running high, some had enough and started having a go back."
Many more travelling fans confirmed that a section of the West Ham support seemed intent on inciting trouble with the 3,000-strong visiting support from Wearside.
One posted on RTG: "I was there today and there was hardly any stewarding after the game and even less police. I haven't seen anything like it in a long time, though I didn't see anyone hurt."
Another fan said: "Outside was ridiculous. It looked like West Ham fans were waiting by our exit to give it the 'biggun' and have a pop at fans trying to get to the bus, to provoke and initiate fights. "
And a third supporter wrote: "There were plenty of police and stewards but they 'manage' the crowd in a bizarre fashion.
"It was the first time in a while we've had to get back to coaches with eyes and wits about you, checking all angles and being alert. There was loads of seniors and women on the coaches. Some of them had never witnessed this before and were clearly concerned."