Park Ji Sung runs to get involved as trouble erupts between United players and Chelsea ground staff

Stewards move in to separate United defender Patrice Evra and Chelsea groundsman Sam Bethell

Bethell is held back by a colleague, while Evra is pulled away by his team-mates

It took three people to restrain a clearly agitated Evra

Evra points at Bethell as he is shepherded away by team-mates following the clash