As during the Cold War, the main cause of the enmity between Sir Alex Ferguson and Arsène Wenger has been a mixture of fear and misunderstanding.

The greatest rivals of the Premier League era meet for the first time in the Champions League this evening. A place in the final is on the line so the stakes have never been higher, but a return to name-calling and mud-slinging is unlikely. “He knows a lot about French wine, which helps,” is Wenger's rather flippant explanation.

A myth has developed that the dilution of the Premier League's longest-running soap opera is the result of Arsenal's decline as a domestic force, but their relationship is far more complex than that. Arsenal were Manchester United's closest challengers for most of last season, as Wenger repeatedly points out, while the ill feeling became most personal at the start of 2005, when Ferguson's side were at their weakest for more than a decade, eventually finishing 18 points behind Chelsea.

However, just a few years later they are regularly seen joking together at Uefa meetings and even shared a stage at a gala dinner held by the League Managers Association last September. Not since Mikhail Gorbachev began raising money for the Ronald W. Reagan Society has there been such a dramatic transformation.

In order to understand the cooling of the conflict it is necessary to revisit its roots, which have more to do with the paranoia, mistrust and petty jealousies endemic in top-level football rather than any genuine hatred. As Mikaël Silvestre, the one man to have played under both managers, makes clear, Ferguson and Wenger have a great deal in common and in different circumstances could have become great friends, or at least developed the kind of master and apprentice relationship Ferguson seems to enjoy with José Mourinho, the Inter Milan coach.

“There cannot be two better managers and they're both natural leaders,” Silvestre said. “They're both really passionate about their jobs and want to be the best. They are hard on themselves and hard with the group. They are first at the training ground and last to leave. They could have been great managers anywhere, not only in sport, but in any other company or business.”

Ferguson has attempted to intimidate his nearest challengers since coming through his difficult early spell at Old Trafford, a tactic that reaped dividends as he succeeded in undermining Kenny Dalglish and Kevin Keegan, but in Wenger found an opponent with the confidence - and, crucially, the wit - to bite back.

As with many used to getting his own way, Ferguson resented the challenge and took umbrage at what he perceived to be Wenger's smart-aleck tone. Many of their initial spats were the result of jokes that backfired, as Wenger confirmed last week when discussing his remark in 1999 that Ferguson must have sent his apology by horse after criticising Arsenal's disciplinary record. “Sending an apology by horse was meant to calm it down, but it didn't work,” Wenger said.

Ferguson's initial envy of this bespectacled newcomer being fêted as an intellectual - “I've got a 15-year-old boy from the Ivory Coast, he speaks five languages,” the United manager said with scorn on Wenger's arrival in 1996 - was exacerbated by the fact that the Frenchman had no time for many of the little traditions of the English game that the Scot held so dear.

Wenger's refusal to share a post-match drink was the source of much immediate annoyance, but in Ferguson's mind a line was crossed when the Arsenal manager failed to shake his hand at the end of that unforgettable FA Cup semi-final replay at Villa Park in 1999.

Ferguson's biggest beef with Wenger concerns Arsenal's disciplinary record, the subject of his first real broadside in 1999. The United manager also developed the habit of taking the moral high ground regarding the lack of English players at Arsenal, but his biggest problem was always their physicality.

“Maybe Arsène was reluctant to accept his own team's discipline issues, where the fact is we all have discipline issues,” Ferguson said.

For all the talk of repeated rows, the most explosive confrontations were concentrated in an 18-month period between the so-called Battle of Old Trafford in September 2003 and the tussle in the tunnel at Highbury in February 2005, with the “Pizzagate” controversy after Arsenal lost their 49-match unbeaten league run in October 2004 providing the meat in a particularly spicy sandwich.

While both managers stood their ground in a war of words off the pitch, the flashpoints were caused by the behaviour of two particularly hot-headed groups of players, with Martin Keown taunting Ruud van Nistelrooy, Cesc Fàbregas allegedly hurling a pizza and Roy Keane urging Patrick Vieira to pick on someone his own size, rather than Gary Neville.

Ferguson believes that the departure of most of those key characters has done more to improve relations than anything else. Fàbregas can start a fight when he is not even playing and the red mist is never far away from Wayne Rooney, but generally both teams are filled with younger, quieter and less aggressive players at the moment.

“There have been confrontations in the past, but one of the reasons was the personalities involved in the two teams at the time,” Ferguson said. “There's mutual respect between Arsène and myself.”

Another important factor has been the emergence of other challengers after eight years in which the Premier League was dominated by two clubs and therefore two men, with Wenger's ire focused on Mourinho, the former Chelsea manager, and more recently Ferguson becoming obsessed by repelling the threat of Liverpool. A greater level of maturity can hardly have been decisive, however, because at the age of 67 Ferguson is still capable of starting childish rows with Rafael Benítez, the Liverpool manager.

Wenger confessed to finding their recent spat “amusing” and is enjoying the peace and quiet, but such is his competitive instinct that another explosion cannot be entirely ruled out if things do not go Arsenal's way.

“It has calmed down,” the Frenchman said. “It was really fierce with the 49th game, which was the most aggressive one, and after that it calmed down because you cannot always be in that kind of situation. He doesn't wind me up. What winds me up is not to win football games. It will be a fierce competition, but our mutual respect will survive the two games.”

Sharing a bottle of Bordeaux at the Emirates Stadium on Tuesday night would provide lasting proof of their entente cordiale.

Ferguson on Wenger

“He's a novice - he should keep his opinions to Japanese football.” April 1997

“Their behaviour was the worst thing I have seen in this sport. They got off scot-free.” Oct 2004

“Arsenal are the worst losers of all time.” Jan 2005

“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.” Jan 2005

Wenger on Ferguson

“Everyone thinks they have the prettiest wife at home.” May 2002

“I will never answer any question any more about this man. He doesn't interest me and doesn't matter to me at all. I will never answer to any provocation from him any more.” Jan 2005

“He has lost all sense of reality. He is going out looking for a confrontation, then asking the person he is confronting to apologise.” Jan 2005