Arsenal's strained relations with Chelsea reached a new low after Arsene Wenger threatened action against Jose Mourinho in reacting with visible anger to being branded a 'voyeur'.
Wenger warned that Mourinho was 'out of order, disconnected with reality and disrespectful' as he declared: 'When you give success to stupid people, it makes them more stupid sometimes and not more intelligent.'
The relationship between the two London clubs has been frosty since the Ashley Cole `tapping-up' inquiry, together with the question marks placed by Wenger over Chelsea's style of play and chief executive Peter Kenyon's stated aim of eclipsing Arsenal as the capital's leading club.
However, Wenger was at a loss to explain exactly why Mourinho had been so directly personal in his verbal attack on him last weekend.
Mourinho had bristled at Wenger's suggestion last week that Chelsea's self-belief may have taken a knock with their draw at Everton and Carling Cup defeat on penalties to Charlton.
After beating Blackburn, the Chelsea boss declared: 'There are some guys, who, when they are at home, have this big telescope to see what happens in other families. He must be one of them. Being a voyeur is a sickness.'
Wenger, who was also accused of being obsessed with Chelsea and coveting Mourinho's job, promptly hit back ahead of Arsenal's Champions League tie against Sparta Prague.
He declared: 'If people say they do not like our game then I can accept that. But when you make personal attacks that are nothing to do with the game, I don't see why.
'It is disrespectful and not acceptable. It is as simple as that. I take the right to take action if it becomes personal like that and that's it.'
The Frenchman would not confirm whether he was considering a complaint to the Football Association for bringing the game into disrepute or even legal action for alleged slander.
'Take that like you want to,' he responded. 'I will see whether I take any action. I don't know yet, but I leave that door open.'
The FA and Premier League intervened when Wenger's verbal sparring with Sir Alex Ferguson degenerated too far last season, with a peace pact enforced on both managers.
No disciplinary action against Mourinho or Wenger is currently planned, although the pressure may yet grow on the governing bodies to get involved again if the row continues to fester.
Wenger did not shy away from confronting the issue as he insisted: 'I'm not obsessed at all with Chelsea. I'm at a club where I'm very happy.
'There wasn't anything malicious in what I said. I was asked a question about Chelsea and I gave an honest answer, just as I expect any other manager to do when he is asked about Arsenal.
'I can't see what is wrong there, or we would all have to close our press conferences. But I will always say what I think as I am a strong personality.'
Tensions are therefore set to remain high between the two clubs ahead of their December 18 clash at Highbury, especially with Chelsea clear at the top of the Barclays Premiership table.
The difference is that while Wenger has relished his psychological battles with Ferguson, with an underlying respect between the two men, there seems little love lost between him and Mourinho.
Wenger continued: 'When I came to England, I was happy to come and be confronted with the English culture, where the owners of the clubs were English and they opened the door to foreign people.
'Now, in some clubs, it looks like it is becoming different and that's where it's important not to lose your values. It is important that the respect you have always shown stays but the ways are becoming different in English football.
'What I will say always is what I think of a game and not of a person - what has that to do with football?
'Is Jose Mourinho rattled? I don't know, but it's not really interesting for me. I don't need an apology, I just need to get on with my job and prepare for our next game.'
That next game is against Sparta, when Thierry Henry will return to help Arsenal secure automatic qualification for the knock-out stages with a victory, enabling them to rest players in their remaining two group ties.
That could help their Premiership challenge, with Wenger refusing to concede defeat in the title race - with another seemingly pointed comment directed at runaway leaders Chelsea.
'I would not be satisfied with second because I think we can come back. There is a long way to go - especially if people get nervous,' he stressed.
That comment will hardly endear him to Mourinho either. Then again, it is still hard to fathom exactly how a man famed for never seeing a controversial incident should be branded a 'voyeur' at all.