The derby between Manchester United Under-21s and their Manchester City counterparts on Tuesday evening has been marred by crowd trouble.
Unrest broke out in Old Trafford's J stand, with heated exchanges between the two sets of supporters forcing stewards to intervene, reports The Mirror.
A pitch invader later entered the field of play before being ushered off by United's Liam Grimshaw.
United won the clash 4-0 in front of 16,000 supporters, who took advantage of free admission, to take a step closer to the Under-21s league title.
