Manchester United boss Sir Alex Ferguson has accused Arsenal counterpart Arsene Wenger of having a "mental problem" when it comes to Ruud van Nistelrooy.
United have been enraged by Wenger's cheat jibe at the Dutch striker in the wake of his horrendous challenge on Ashley Cole last Sunday.
Van Nistelrooy was also heavily criticised by Wenger following the sending off of Patrick Vieira in last season's Old Trafford tussle between the two sides.
"The guy has obviously got a mental problem with Ruud van Nistelrooy for some reason. It's always Ruud van Nistelrooy," said Ferguson.
"Ruud has accepted responsibility and held his hands up. Having seen the video of the incident, Ruud can't believe how high his knee was.
"He was trying to bring his foot down on to the ball to turn back into Sol Campbell, but he accepts his responsibility and we do too.
"Wenger obviously has a problem with him. I can't understand it, I really can't. But Ruud knows that he has the support of all the club and that's the important thing."
Having admitted a charge of serious foul play, Van Nistelrooy has now served one game of an automatic three-match suspension.
Arsenal vice chairman David Dein met with United chief executive David Gill in Manchester on Wednesday in an attempt to diffuse the tension between the two clubs.
But, after acting in what they view as a responsible manner over the Dutchman's conduct and the tunnel bust-up which followed the match, United have again been upset by Arsenal's approach to the whole affair.
Wenger has continuously claimed nothing happened in the tunnel, while Gunners midfielder Edu launched another scathing attack on United's roughhouse tactics in midweek.
"At the moment what we are doing is saying nothing and we believe that to be the correct attitude," added Ferguson.
"There was supposed to be an agreement between the two clubs that neither would say anything, but that has obviously been washed aside by Arsenal's actions during the week.
"I wasn't surprised that Arsenal spoke out, however, and I told our chief executive, David Gill, that it would happen."
The on-going feud will spill over into Soho Square next week when Red Devils officials dump an explosive dossier on the Football Association chronicling the Battle of Old Trafford II.
"What we are doing at the moment is collating a lot of information about Arsenal and of what happened last week," said Ferguson. "We will present to the FA video evidence and statements from independent witnesses and that's important.
"It's up to the FA as to any punishment that Arsenal may receive, but what we send will be so clear-cut that they will need to do something. Arsenal have a past record and sometimes you run out of excuses."