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.