But even without the Luis Suarez-Patrice Evra racism row hanging over Saturday's FA Cup Fourth Round meeting at Anfield, a match between English football's arch rivals is never just a game.
Just ask the United fans sporting the "Liverpool 18, Manchester 19" T-shirts, referring to league titles won, or the Liverpool supporters waving the "We're not racists, we only hate mancs" banner.
While much of the rivalry is acerbic banter, hostility can boil over and turn physical and the chants can become abusive.
Such is the intensity of a Liverpool-Manchester derby that Ferguson wrote to his travelling fans this week urging them to give "positive, witty and loud" support, respect stewards and follow the ground regulations.
Forgetting the gloating over who has won more league titles (United) and European Cups (Liverpool) and a rivalry between two north-west cities stretching back to the Industrial Revolution, this weekend's meeting has a fresher fish to fry.
The cup match is the first meeting between the teams since Liverpool striker Suarez was given an eight-match ban for racially abusing United left-back Evra in their Premier League game at Anfield in October.
Ferguson steered clear of the issue on Friday with a terse "I'm not getting involved in that, right" when asked whether his French defender would be playing in the match, which comes as Suarez is still serving his ban.
"At the end of the day we want to talk about a game of football," Ferguson said.
"It's a big FA Cup tie - there's no doubt about it.
'MASSIVE GAME'
"And both sets of fans need to make sure we're talking about the game and nothing else. It can be that way because there are plenty of good players on the pitch," he added.
"You just have to concentrate on the game. That's what you have to do, just try and play your game. That helps. I think both sets of players are aware of that. I'm confident there won't be problems."
He backed Liverpool captain Steven Gerrard's call for both clubs "to ensure that this game is remembered for the football," saying he expected his players to behave properly.
Ferguson, whose team's season has been disrupted by injuries, was expecting to get "two or three" players back to training on Friday without saying who they might be.
Centre-back Rio Ferdinand missed last weekend's win over Arsenal with a back problem, while fellow defender Phil Jones came off with an ankle injury and winger Nani hobbled off too. Wayne Rooney, Michael Carrick and Evra also picked up knocks.
Saturday's match has another great rivalry at the heart of it with Ferguson coming up against Kenny Dalglish, who was the man to beat when Ferguson arrived at Old Trafford in 1986 and Liverpool were enjoying successful times.
Last season he fulfilled his vow to "knock Liverpool off their perch" by leading United to a record 19th league title and Ferguson believes his feat of being in charge of the club for 25 years will never be repeated.
