Jurgen Klopp's recent suggestion that the Red Devils get favourable treatment when it comes to penalties has ensured the match officials are under scrutiny before a ball's even been kicked.
Throughout Premier League history, this fixture has had plenty of famous refereeing decisions including one or two notable red cards.
There was Steven Gerrard kicking Ander Herrera less than a minute after coming on as a substitute - and that was his final appearance against Liverpool's old rivals.
Or how about Nemanja Vidic capping one of his worst performances for United by bringing down Gerrard after being terrorised by Fernando Torres all afternoon?
Yet there's one sending off which eclipsed them all for madness and that was Paul Scholes back in 2007.
When we tell our grandchildren about what a fine player the legendary midfielder was, it won't be for his disciplinary record. Scholes' tackling was notoriously awful and even extended to getting sent off against Porto in a glorified pre-season friendly.
On Merseyside, however, he made no such attempt to get the ball in a bizarre altercation with Xabi Alonso.
When Scholes lost it
Scholes initially seemed to be guilty of a handball but as he played on, the Spaniard pulled at his other arm. Incensed, Scholes turned round and swung for him - imagine if he'd made contact! It's a good job his punches weren't quite as accurate as his passes.
In his 20 years at Old Trafford, the former England international received four red cards and 97 yellows, but none of them were as crazy as that one.
Martin Atkinson had absolutely no choice but to pull a red straight out of his pocket.
In the years since their departures from the Premier League, Alonso and Scholes have drawn plenty of comparisons. Who had the better long pass in their locker? Who could shoot better from range?
At least we know who had the better right hook...
Even if there aren't any major flashpoints between Liverpool and United on Sunday, we are still in for a treat of a spectacle thanks to Ole Gunnar Solskjaer's side's surprise tilt at the title.
Working against the visitors is that they haven't won at Anfield in five years - and of course, Liverpool haven't lost to any opponent in the Premier League at home since April 2017.News Now - Sport News