Arsène Wenger talked like a man who seemed to have forgotten he and Sir Alex Ferguson were supposed to have called a ceasefire. What was the difference, he was asked, now Ferguson was no longer in the Manchester United dugout? Arsenal's manager could not resist the temptation. "That's a question you shouldn't ask me but the referees," he said.
By that stage he had already suggested René Meulensteen, one of Ferguson's coaches, had tapped up Robin van Persie, a player he still regards very much as "an Arsenal man".
Now he tried to explain how United would be affected without the Ferguson factor, and the number of points they might lose as a direct result. "Every year there is a company that makes a league table of what it would be like without the referees' mistakes. So check that. Ask the referees. If I had a good sense of humour, I would tell you the difference."
His next reference to Old Trafford, reflecting on the Ferguson era, was thick with sarcasm. "I think the referees were absolutely relaxed and happy to go there."
It was the kind of line that used to be synonymous with these fixtures and perhaps it told us something about Wenger's mind-set that he was willing, virtually unprompted, to return to the days when every United-Arsenal game was preceded with allegation and counter-allegation.
Shortly beforehand he had been asked whether Arsenal, in the previous few years, had gone to Old Trafford with more fear than confidence. "A little bit, yes," he replied. But not any longer, with a five-point lead at the top of the Premier League, eight clear of David Moyes's team and coming off a week in which they won at the home of Borussia Dortmund, last season's Champions League finalists.
Wenger's throwback nibble at United comes with the Arsenal manager in a new position of strength. It felt premeditated. He was smiling, knowingly, as he said it and, at times, it seemed like a man challenging to be alpha male now Ferguson was not around. In other moments Wenger strayed dangerously close to breaching the FA's rules forbidding managers from talking about referees before games.
His team have won only one of their last 11 encounters on United's ground. They have had more defeats at Old Trafford than anywhere else in the Premier League era and, among all the indignities Wenger has suffered in recent years, the 8-2 walloping in August 2011 will always be the nadir.
"Their heaviest defeat since 1896, when they lost 8-0 to Loughborough Town," as Ferguson helpfully points out in his autobiography. "It could have been 20. It actually reached the point where I felt – please, no more goals. It was a humiliation for Arsène. The climate at Arsenal was hardly serene to begin with. But we played some fantastic football that day. With the missed chances on either side, it might have been 12-4 or 12-5."
Yet Arsenal now, compared to then, are barely recognisable. "We rush less, we do not panic," Wenger said. "We believe we can get a result on Sunday. We go there like we go everywhere, to control the game and to win the game. Every season we have done well, winning the league, we have always won at Old Trafford." Sunday, unmistakably, is one of those occasions that will count for much more than just three points.
"One of the benchmark games … a game when you can judge how strong you really are." To win, he is acutely aware, would lay down the biggest marker yet that Arsenal's title challenge has to be taken seriously.
Wenger clearly wants to see whether opposing teams will get the raw deal at Old Trafford that he suspected was always the case in the Ferguson years. He also cited Ashley Young as a player he wanted the referee to monitor closely.
"In England people try to cheat the referee and try to dive. They get a quick, negative reaction from the press and that's the best way to get it out of the game, whether it's Ashley Young or one of my players. I am happy that the press responds."
Later Wenger expressed another suspicion, that United might resort to overly physical tactics if Moyes suspects Arsenal are the superior side. "It's down to the referee to make the right decisions, to protect the players and to give the free-kicks you deserve," he said.
At Old Trafford, he continued, it was not just the manager who could influence decisions. "The pressure comes from the crowd as well. They go for every ball and put the referee under pressure. That happens more in the north than in the south. You know when you go to Sunderland the crowd plays every ball. When you go to Everton the crowd plays every ball. Then in London the crowd is a bit more relaxed."
No doubt there is a chance he might bump into Ferguson anyway. He was looking forward to it, he said, and he sounded as if he might even mean it. "It's easier now, a bit more pacific. We don't fight against each other now. We meet each other only at the [Uefa] managers' meetings and speak about how we can improve football, not how Manchester United can beat Arsenal, or how Arsenal can beat Man United. So, of course, it will be a bit more peaceful and serene."
Yet the impression here is they will always be the neighbours arguing over the garden fence about who has the tidier lawn. Ferguson's account of the Van Persie transfer, as told in his book, is that it was his telephone call, direct to Wenger, that swung the deal. "Honestly, what convinced me in our talks was only his number [transfer fee]," Wenger replied. "It was the conversations I had with Robin that convinced me, not Alex Ferguson."
But there was more to it than that, he added. "Robin has been convinced by the Dutch coach [Meulensteen] who was at Manchester United. That played a big part." Nobody from Old Trafford should have been speaking to Van Persie.
Van Persie will certainly have his work cut out against Per Mertesacker and Laurent Koscielny, both of whom have played superbly this season, and Wenger believes it is time his renascent defence started to get more acclaim.
He reflected on all the praise that traditionally comes the way of Arsenal's most famous back four – Lee Dixon, Tony Adams, Steve Bould and Nigel Winterburn – but the downside, he said, was that it sometimes counted against the defenders who have excelled since. "People forget the defence that helped us go unbeaten [in the 2003-04 season]. They never speak about them at all and it's unbelievable that defence never gets any credit. Lauren, Kolo Touré, Sol Campbell and Ashley Cole – they didn't lose a game and yet no one speaks about them."
Now, he said, it was time for his current defence, often derided, to be recognised. "They have the quality individually, they have the confidence and they certainly complement each other well. We have more confidence.
"We have improved … the defensive urgency, the defensive focus of everybody from the first minute to the last minute. You couldn't feel, in any moment of the Dortmund game, that our concentration level dropped."
If nothing else, Wenger is entitled to think the days are gone when his star players wanted to leave. "Robin was 29 and impatient. Of course it's strange because, for me, he's an Arsenal man.
"But we have gone through years when we had to be tight financially. Some players saw the other big clubs buying world-named players and, of course, they lost a little bit of confidence that we can compete with them.
"It's understandable but I think we have always been consistent in the way we thought the club had to be run and that at some stage we could turn the corner. Hopefully we have done it this year.
"We still think the best way to win at Old Trafford is to control the game. Take the ball, keep the ball and have more possession than they do.
"We have a little advantage. We have to use that in a positive way because our hunger will be tested there. How much do we take advantage or do we just go there and say: 'Let's see what happens'?"
He sounded like a man who would be telling his players one thing: to find out if it were true, post-Ferguson, that Old Trafford was no longer such a formidable venue.