A West Ham supporter sat in a section of a stadium attacked by AZ Alkmaar fans after the Europa Conference League semi-final said there were no police nearby and stewards could not cope.
Several West Ham players confronted the group that had attacked the area that contained their friends and family.
Russell Raphael described the incident at the AFAS Stadion as “scary”.
“There were stewards there but no police to stop them,” Raphael told the BBC News Channel.
“More than 30 of them in balaclavas somehow breached their area and were running towards us.
“Some very brave West Ham fans, about 10 rows to our right, were doing their best to stop them, the stewards were doing their best.
“The players instead of celebrating with the main away support panicked and saw their families being threatened, so they very understandably ran to get involved.
“These [fans in] balaclavas, hooded, all dressed in black, it is a scary thing and we were very lucky not to be physically involved.”
Michail Antonio and Said Benrahma were among the players who tried to intervene, while the 87-year-old father of West Ham manager David Moyes was reportedly sat in the stands in the Netherlands.
It is understood the families of the players were unharmed.
West Ham won the game 1-0 for a 3-1 aggregate victory.
“The security going in was fine. You expect to be herded like cattle in these away games, that’s the way it is,” added Raphael, who watched the match with his son, Aidan.
“They kept us back for a long time after the game and there was a lot of police going out. I didn’t feel in danger around the ground. In the ground it was just stewards who were clearly unable to cope with what was going on.
“It must have taken 10 minutes for the police to arrive.”
European football’s governing body Uefa will review reports of the incidents before deciding on any action.
Dutch police said they were investigating footage of the incident but no arrests had been made.
“I was disappointed because I felt like it took the attention off the team and what we did,” said Moyes on Friday.
“There was nothing we could do, or that West Ham as a club could do. Like anyone, if you saw your family members in trouble then you’d go and help out and that was the situation.
“Unfortunately it’s taken up a lot of the news and time. But we’re not letting it take away from the fact we reached the final, which is a brilliant achievement.”
AZ Alkmaar manager Pascal Jansen said he was “a little bit ashamed” that the incident had happened in their stadium, while Pantelis Hatzidiakos was one of several AZ players who condemned the violence.
“I think it’s sad what happened. My family was up there. I have been in contact with them and my girlfriend said they were shaking,” the Greece defender told Dutch television.
“I don’t even call them supporters. Just stay home if you have such intentions.”
