Arsene Wenger claims Sir Alex Ferguson has lost "a lot of credibility" during the pair's latest high-profile row.
The Arsenal manager called on Monday for his Manchester United counterpart to be put on a disrepute charge over comments made in a weekend interview.
Ferguson said Wenger's conduct in the wake of United's 2-0 win over Arsenal in October had been "a disgrace".
Now Wenger has told French television station TPS: "Ferguson's out of order. He has lost all sense of reality."
Ferguson re-ignited the feud between the duo in an interview with The Independent on Saturday, claiming Wenger owed him an apology for being threatening after that match at Old Trafford.
The Arsenal boss believes Ferguson should be punished by the Football Association for increasing tension ahead of the return fixture at Highbury on 1 February.
Wenger then told the French station: "He is going out looking for a confrontation, then asking the person he is confronting to apologise.
"He's pushed the cork in a bit far this time and lost a lot of credibility by saying what he said."
The Gunners chief also turned a conversation with the channel about video replays in football into a barb at United.
"We need to introduce video replays as quickly as possible," said Wenger.
"If you take the example of Manchester United, they would be in mid-table now if officials had the benefit of video replays."
That was a reference to Tottenham's goal at United earlier in January, when Pedro Mendes' shot clearly crossed the line but was not seen by the referee.
Wenger's new outburst comes after he initially, on Saturday, refused to bite back at Ferguson, saying only: "I will never answer any questions any more about this man."
Ferguson had told The Independent: "In the tunnel Wenger was criticising my players, calling them cheats, so I told him to leave them alone and behave himself.
"He ran at me with hands raised saying 'what do you want to do about it?'
"To not apologise for the behaviour of the players to another manager is unthinkable. It's a disgrace, but I don't expect Wenger to ever apologise, he's that type of person."
Those allegations were put to Wenger after Saturday's game at Bolton, which Arsenal lost to slip 10 points behind Chelsea in the title race.
At first he said only: "I've always been consistent with that story and told you nothing happened.
"If he has to talk, he talks. If he wants to make a newspaper article, he makes a newspaper article.
"He doesn't interest me and doesn't matter to me at all. I will never answer to any provocation from him any more.
"He does what he likes in England anyway. He can go abroad one day and see how it is."
But later on Saturday, according to The Independent, Wenger spoke to a smaller group of reporters and expanded on his reaction.
"I have no diplomatic relations with him," the Arsenal boss is quoted as saying.
"What I don't understand is that he does what he wants and you (the press) are all at his feet.
"The situation has been judged and there is a game going on in a month.
"The managers have a responsibility to protect the game before the game. But in England you are only punished for what you say after the game."
Reminded that Ferguson called him "a disgrace", Wenger added: "I don't respond to anything. In England you have a good phrase. It is 'bringing the game into disrepute'.
"But that is not only after a game, it is as well before a game."
MAN UTD v ARSENAL FALL-OUT
24 Oct: Man Utd 2-0 Arsenal. Wenger is accused of calling Van Nistelrooy a "cheat", for which he is fined £15,000
26 Oct: Wenger accuses United of "kicking Reyes off the park"
15 Jan: Ferguson calls Wenger's behaviour a "disgrace" and says Arsenal are "the worst losers of all time"
16 Jan: Wenger says he will "never answer any question any more" about Ferguson
16 Jan: Wenger changes his position, accusing Ferguson of bringing game into "disrepute"
17 Jan: Wenger says Ferguson has "lost credibility"
Ferguson had also claimed that United chief executive David Gill and Arsenal vice-chairman David Dein had agreed at boardroom level not to discuss the incident in public.
But Ferguson added: "In the ensuing weeks all you got was a diatribe from Arsenal about being kicked off the pitch and all that nonsense. Gill phoned Dein three times to complain but nothing was done.
"The return is on 1 February and they will come out with another diatribe.
"David Gill and I feel we should set the record straight because Arsenal have not written to us to apologise and we would not let that happen here."