Liverpool - Alex Ferguson once described Liverpool versus Manchester United as the biggest fixture in club football and Monday's clash at Anfield has been made all the more intriguing by the debate over the form of Wayne Rooney.
United's captain, dropped to the bench by manager Jose Mourinho for his club's last three fixtures, suffered the same fate with England during last week's goalless draw away to Slovenia in a World Cup qualifier.
Rooney has faced heavy criticism lately, yet Liverpool manager Jurgen Klopp is still wary of the forward cum midfielder, who scored the only goal as United won in the Premier League at Anfield in January.
"I know a lot of what everybody thinks at this moment about Wayne Rooney and I cannot think the same things, even as the manager of Liverpool FC," said Klopp.
"He is 30 years old and has had a very long and more than a decent career in the Premier League. The longer you are part of something, the more people know about you and think they can say about you," the German added.
"Why does anybody think that Jose Mourinho is blind from one second to the other and says, 'OK, he's not good enough any more but he's still playing'? Or why do they think Sam Allardyce (the former England manager) did it, or why Gareth Southgate (the interim England boss) did it? They all know about his quality and know about his value for each team he plays in."
Despite Klopp's kind words, Rooney may well have to settle for a place among the substitutes again as United seek to deny Liverpool a victory that would see the Merseysiders go level on points with Premier League leaders Manchester City.
As well as Rooney's form, another sub-plot that has emerged in the build-up to the game concerns referee Anthony Taylor.
The fact Taylor is based in Manchester has led to complaints about the official's objectivity, even though he supports non-league Altrincham.
Former top-flight referee Keith Hackett said Taylor should not have been put in charge of the match as the "focus on him would be intolerable" should he make an error on Monday.
Meanwhile some Liverpool fans have suggested that Taylor ought to get the same treatment as Kevin Friend.
The Leicester-based referee was removed from Tottenham's game at Stoke in April, with Spurs then battling the Foxes, the eventual champions, for the title, in order to prevent accusations of bias.
A concerned Mourinho, not averse to criticising referees, suggested the pre-match scrutiny had done Taylor few favours.
"I think Mr Taylor is a very good referee but I think somebody with intention is putting such a pressure on him that I feel that it will be difficult for him to have a very good performance," he said.
Liverpool go into Monday's game seeking to end a run of four straight league defeats against their bitter northwest rivals, but having also knocked United out of last season's Europa League.
Klopp, whose team left it late to gain a 2-1 victory at Swansea in their last league match, is hopeful that Georginio Wijnaldum (hip) and Adam Lallana (groin) will recover from injury problems in time to feature on Monday.
Mourinho is hopeful that left-back Luke Shaw (groin) and midfielder Henrikh Mkhitaryan (thigh) will be available to play at Anfield following their recent injuries.
United suffered a run of three successive defeats last month had consecutive wins across three competitions against Northampton, Leicester and Zorya Luhansk calmed the panic, although a 1-1 draw at home to Stoke before the international break stalled the recovery.
Mourinho, who has won one and lost three of his previous five meetings with Klopp, will hope for an improvement at Anfield.
United forward Jesse Lingard, seeking to maintain personal momentum after he made his England debut during the recent international break, said: "It'll be tough because they (Liverpool) have got a lot talent in their group, but we know we've got talent in our own ranks.
"We'll be pushing to win the game as it's always good to get one over your rivals."