Manchester United's tunnel bust-up with Liverpool on Saturday afternoon was caused by an opposition player spitting at United goalkeeper David de Gea, according to The Sun.
The police were called as both sets of players clashed at the interval, and a source has stated that the brawl was sparked by a spitting storm.
"De Gea was making his way down the tunnel and was clearly shocked to be spat at. Obviously the players reacted angrily and both teams became involved, before stewards managed to quieten it down," said the source.
Tempers also frayed at the end of the match when United defender Patrice Evra appeared to celebrate in front of Liverpool's Luis Suarez, while Craig Bellamy reportedly got involved in a confrontation with the Old Trafford head of security.
