It was an unusual sight: the first Manchester United game of the season and on the forecourt of Old Trafford the Liverpool manager, Roy Hodgson, signing autographs and politely fixing a smile while supporters snapped at him with mobile phones – unusual because the tribalism and history surrounding these clubs means Sir Alex Ferguson has to plan his visits to Anfield like a military operation.

Ferguson remembers one spying mission on Merseyside when the greeting as he got out of his car was "You Manc bastard, come to see the champions?" There is old footage of him being jeered and harassed as he is escorted to the ground by two policemen, with the club's head of security close by. The United manager is doing a pretty good job of pretending he is oblivious to the Liverpool fan repeatedly shouting (expletives removed): "You must be lost mate, wrong ground."

But Hodgson inspires different emotions. The United fanzine Red Issue has begun a cartoon strip – "Watch Out It's Woy Boy" – mocking the way he pronounces his Rs (no wonder Albert Riera has been sold) but it is not malicious stuff. On Sunday, when the two clubs renew hostilities at Old Trafford, the home crowd may find it unusually difficult to conform to tradition and instantly regard him as a reviled enemy and that is certainly so for Ferguson, given the strength of a friendship dating back over 20 years.

Ferguson's relationship with the previous Liverpool manager, Rafael Benítez, had reached the point where he would refer to the Spaniard only by his surname and their handshakes at the end of matches were wonderfully orchestrated manoeuvres of contempt – no eye contact whatever, the briefest of touches, already moving in opposite directions, an operation freighted with cold disdain.

The animosity lingers. Ferguson was asked earlier this season about Benítez moving to Internazionale and José Mourinho to Read Madrid and "those permutations considered, do they favour United?" A smile crossed his lips. "They favour Madrid, no doubt about that," he replied.

Hodgson, on the other hand, counts as a personal friend, someone with whom he has spent many a night putting the world to rights. The two men share many things: a love of red wine, storytelling, politics, books, nostalgia and, most of all, football. Hodgson, at 63, is five years younger than Ferguson but closer to him in age than any other manager in the Premier League and sees him as being on his wavelength. Their biggest difference is that Hodgson's feelings towards Sam Allardyce, one of Ferguson's allies, are similar to those held by the grudge-collector Benítez. As for Hodgson's opinion of Ferguson, it is simple: "In my working lifetime I regard him as the greatest manager in English football."

In the Benítez years the press conferences before these matches had an undercurrent, occasionally spilling over into open hostility. Today they were cordial events, the two managers respectful of one another, with only good things to say.

"I know Alex is not really a Liverpool man but I've spoken to him and, in a jocular way, I asked that now I have this job we don't speak to each other," Hodgson said. "He didn't put the phone down. He made some cutting remark but I can't remember what it was." He believes they will share a bottle of wine at some point, though "maybe in secret".

In return Ferguson told the story of how they met one night in Malmo in 1987, when he had flown to Sweden only for the game to be called off inside the first few minutes. A 40-year-old Hodgson was managing Malmo at the time and got wind that the United manager had made a wasted journey. "It was a European tie against Ajax and we went to dinner," Ferguson recalled. "I've known him a long time now. He's gathered a wealth of experience in Italy, Switzerland, Finland and Scandinavia and the job he did last season at Fulham was extraordinary" – so good that Ferguson voted for him to be named the League Managers Association's manager of the year.

Later it was put to Ferguson that Hodgson's appointment had taken some of the sting out of the game because there were no longer personal issues between the rival dug-outs.

"I must correct you right away," he replied with a flash of indignation. "I've never been personal. You'd have to examine him [Benítez], not me. I've always enjoyed a good relationship with the Liverpool managers and both clubs have always addressed the situation properly after games. That changed under the last regime but it's not a big issue for me."

One certainty, though, is that the handshake at the final whistle on Sunday will be markedly different from the previous few seasons.

"I've always believed you don't have battles with other managers," Hodgson said. "Football teams have battles with other football teams, clubs have battles with other clubs. I've never subscribed to the theory that it's me and you. The 70,000 at Old Trafford turn up to watch the 22 actors on the field, not Alex and myself."