Players' chief Gordon Taylor has condemned the fracas which marred the end of Manchester United's clash with Arsenal at Old Trafford yesterday.
Taylor, chief executive of the Professional Footballers' Association, spoke out following Patrick Vieira's sending off after he kicked out at Ruud van Nistelrooy late in the 0-0 draw at Old Trafford.
Van Nistelrooy then hit the bar with an injury-time penalty and was taunted by several Arsenal players, including old foe Martin Keown, both immediately afterwards and on the final whistle.
"There's no use dressing it up, it's been a bad weekend," Taylor said. "What took place yesterday - and there were other incidents - is just not acceptable and has to be addressed."
Taylor acknowledged that the PFA have a role to play in addressing the situation, but called on managers as well as players to exercise greater responsibility.
"They are high-profile players being well-paid, and that comes with a responsibility, a collective responsibility from all players and managers to show respect for each other and respect for referees. We can't have the scenes we had yesterday and we can't condone that in any way."