Several Manchester United fans attacked Brentford supporters before the two sides met on Monday.
Video footage shows United fans rushing towards the Bees fans as they made their way towards the visitors' entrance at Old Trafford before kick-off.
Missiles were launched, punches thrown and flares set off in distasteful scenes amid an angry atmosphere, with widespread frustration at the deeply unpopular Glazer family that owns the club.
Manchester United fans were filmed attacking Brentford supporters on Monday night (above)
United supporters rushed towards their Bees counterparts as they tried to enter Old Trafford
A long line of police officers (right) intervened to de-escalate the tension outside the ground
Riot police were forced to intervene to prevent the clashes between the fans spilling over into outright violence.
United supporters, seemingly the aggressors, sung loud songs, most notably about wanting part-owner Joel Glazer dead.
They chanted 'Gonna die, gonna die, Joel Glazer's gonna die' while piling towards the opposition fans, only prevented from clashing directly due to the ring of riot police and security staff.
The end of the video shows a long, linked line of police officers with masks and helmets on to protect themselves from smoke and potential attacks.
'Love United, hate Glazers' and 'United are the team for me' were also sung, with smoke from red and green flares billowing around, amid the anti-Glazer protests which have been ongoing for the last month or so.
Once again fans gathered outside the ground, chanting anti-Glazer songs.
Some Man United fans encouraged others to walk out in the 73rd minute at home to Brentford
The campaign did not have a considerable effect, although some fans were spotted departin
Previous protests have involved fans boycotting
