In the past six meetings between Manchester City and Liverpool in major competitions Pep Guardiola used notably different tactical setups on each occasion.
Defensive problems with a 3-5-2 despite a 5-0 win over the 10-man Reds in September 2017 prompted a switch to his tried and trusted 4-3-3 as City swept all before them on the way to a 100-point haul and Premier League glory in 2017-18.
Well, almost all. Liverpool won a thriller 4-3 on Merseyside in the January of that campaign – persuading Guardiola to select a diamond midfield for the first leg of a Champions League quarter-final three months later.
That didn't work either, as City were ransacked 3-0 and were unable to turn the tie around despite an all-or-nothing 3-1-4-2 line-up tearing into the return leg at the Etihad Stadium with gusto.
Last season it was out with the cavalier and in with control, whether that was Bernardo Silva playing in a deeper central midfield position during a 0-0 draw in Liverpool or Aymeric Laporte playing on the left of a defence able to pivot from a four to a three in a gripping 2-1 triumph in Manchester.
City will search for a first Anfield win in 16-and-a-half years on Sunday, with Liverpool's six-point lead at the top of the Premier League table compromising their ambitions of a third straight title.
Ederson this week joined an injury list featuring Aymeric Laporte, Leroy Sane, David Silva and Oleksandr Zinchenko, meaning an even taller order for Guardiola against the most persistently challenging adversary of his coaching career.
Here, we look at how Guardiola might approach his latest crack at the Klopp conundrum.
4-4-2, 1-4-4-1 – Guardiola's 2019-20 shape experiments
During August's Community Shield encounter against Liverpool, where a typically tight game went City's way on penalties after a 1-1 draw, Guardiola debuted a tweak to his 4-3-3. One of the attacking midfielders – in this instance Kevin De Bruyne – would press high and close to the centre forward, forming a 4-4-2 shape without the ball.
Ostensibly, this ploy has been designed for an aging David Silva to be able to press in a more economical fashion. The master playmaker is likely to miss out at Anfield with a muscular injury, however, and namesake Bernardo seemed a good fit for the role during the first half against Atalanta.
The Portugal international's positioning allowed him to play an astute pass to create Raheem Sterling's opener after the goalscorer won back possession with an interception.
Expect to see more of that when the hosts have the ball, while a new configuration when building play from the back might be used to try and neutralise Liverpool's formidable press.
Ederson's supreme ability with the ball at his feet is simply not replicated by Claudio Bravo, despite the Camp Nou credentials of the man who will deputise for City's injured Brazil international.
This will undoubtedly compromise the construction of the visitors' attacks on Sunday, meaning Fernandinho's accelerated progression from makeshift to mainstay at centre-back is likely to be locked in.
A notable ploy in the games against Crystal Palace away and Atalanta at home, when Guardiola paired Fernandinho with fellow defensive midfielder Rodri in the heart of defence, was one of the centre-backs moving alongside the holding midfielder when City started their build-up.
This created another passing option for the goalkeeper and deeper centre-back and amounted roughly to a 1-4-4-1 shape.
Fernandinho's superb passing range and John Stones' smooth style being suited to this approach means there is another argument for Nicolas Otamendi being the odd man out in defence, before considering his ranking alongside Bravo in the accident-prone stakes.
A time for Foden?
Ever since his maiden first-team appearance two years ago, the understandable clamour for boyhood City fan Phil Foden to feature more frequently has steadily grown.
The difference this season is a case can be made beyond romanticism and the importance of the 19-year-old's development; in certain matches and situations, City look better with Foden in the side
He dazzled for the most part when he started the 5-1 win over Atalanta, only to blot his good work with a pair of needless late bookings. That red card is a reason for Guardiola to stick with more tried and tested names, but he cited the England Under-21 star's box-to-box capabilities as the reason for his selection and frequent success against the Serie A side.
The playmaker's presence lends a dynamism to City's midfield that was notably lacking from this season's Premier League defeats to Norwich City and Wolves, and meeting Liverpool's verve and energy head on feels like a must.
Guardiola's midweek trident of Gundogan, Bernardo Silva and De Bruyne might well have been road tested with Anfield in mind, but throwing Foden into a high-stakes encounter – as when he scored the winner in last season's vital 1-0 victory over Tottenham at the Etihad Stadium – is being given strong consideration.
"Phil Foden has a great stamina capacity, a great thing against Liverpool," a source close to Guardiola told Omnisport before David Silva's injury made Foden's path to the first XI theoretically more straightforward.
"I think City are not interested in a crazy match versus Liverpool, but to try to be in control of the ball. But finally, that [picking Foden] is the crucial decision around Pep's match plan."
Aguero or Jesus… or both?
Sergio Aguero has started 2019-20 in typically prolific form, scoring 13 times in 14 appearances, despite sometimes appearing to be operating shy of top gear.
At the same time, Gabriel Jesus is also enjoying a strong run of form and, given Guardiola's frequently stated admiration for the Brazil striker's high-pressing, there could be a temptation to switch his attacking spearhead.
However, as separate as it remains from what he brings in open play, Jesus' feeble penalty at San Siro will not have helped his case. Also, Aguero's pedigree in big games – even allowing for the anomaly of him never finding the net at Anfield – surely sways the argument in his favour.
Jesus' revival after an underwhelming 2018-19 came playing on the right-hand side of Brazil's attack. Guardiola has not played Aguero and Jesus together in the same 4-3-3 forward line with any frequency since the early months of 2017-18 and a bold Jesus-Aguero-Sterling frontline would certainly raise eyebrows on Merseyside.
It could also cause plenty of problems. Nevertheless, Bernardo Silva's tireless work rate to negate Andy Robertson or Riyad Mahrez looking to atone a wretched penalty miss of his own on the same ground 13 months ago remain far more likely options on Guardiola's right flank.
Omnisport's predicted Manchester City line-up to face Liverpool: Bravo; Walker, Fernandinho, Stones, Mendy; Gundogan, De Bruyne, Foden; Bernardo Silva, Aguero, Sterling.