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The departure of David Moyes from Everton prompted an abundance of rumours linking all sorts of managers to the post - from the likes of Vitor Pereira, the unknown, "continental" quantity, to Malky McKay, the more traditional, "English" coach. In the end, they settled for the in-between option: Roberto Martinez, who'd just seen his Wigan side both be relegated and win the FA Cup in the space of seven days.
Such contrasting fortunes threw doubt over his credentials to take over a top-half side like Everton. A major critique of his Wigan side was their inconsistency - by and large, they were awful, only surviving relegation from the Premier League in recent years because of somewhat inexplicable, yet incredible form.
In 2011-12 the turnaround in fortunes was widely attributed to Martinez's bold formation switch from 4-3-3 to 3-4-3 - it was rare for teams to encounter three at the back in England, and the element of surprise was certainly a crucial factor.
It was so successful Martinez switched to it permanently in 2012-13, and so understandably the key tactical question surrounding his move to Everton was whether he'd introduce it to a team so entrenched in Moyes' preferred 4-2-3-1. The difference between the latter's intense emphasis on disciplined, organised two banks of four and Martinez's more open, unorthodox approach is enormous - and fittingly, Everton so far in 13-14 have been torn between two approaches. They are dominating possession - 64%, the highest in the league - but it has been sterile dominance, with the cutting edge that Everton often lacked under Moyes still conspicuously noticeable despite the change in coach.
Romelu Lukaku, with his deadly combination of pace and power, is ideal for helping Everton turn possession into penetration, but the Chelsea loanee is ineligible against his parent club - so either Aroune Kone or Nikica Jelavic will start upfront in a 4-2-3-1. Kone's movement is more intelligent and he will drift towards the left to create overloads - but Jelavic appears to be in favour, despite a lack of form.
Instead, Everton will look for attacking inspiration from the band of three, which is the zone in which Martinez's changes are most obvious. Ross Barkley, rather than Marouane Fellaini, now occupies the central attacking role, and the difference between the two is obvious - the latter offers physical hold-up play, whereas Barkley is more technical and will drop deep to link up with the two deeper midfielders via neat passing triangles.
It'll be worth keeping an eye on the battle in deep midfield, where Martinez could feasibly hand debuts to two deadline day signings, Gareth Barry and James McCarthy. Both are upgrades on Darren Gibson and Leon Osman, and should give Everton a more solid feel in front of the defence - and it'll be interesting to see, should Barry start, what sort of role he plays. Martinez has been gushing about the Manchester City loanee defensive qualities, and having asked John Heitinga to drop back in between the centre-backs to create a back three in pre-season, it's not unfeasible that Barry could perform that role here.
Meanwhile, the familiar combination of Steven Pienaar and Kevin Mirallas will start on the flanks. The Belgian will play higher up and dribble directly towards goal, so Jose Mourinho might ask Ashley Cole to stick tight and prevent him from moving inside into shooting positions - the same instructions Roy Hodgson asked of the left-back midweek in England's clash with Ukraine.
On the left, Steven Pienaar will too move narrow - crucial, as it opens up space for Leighton Baines to overlap. Everton's threat from the full-back positions has long been obvious, with Baines capable of providing a stream of steady crosses from the flank, and that has only become more prominent under Martinez. On the opposite side, meanwhile, Seamus Coleman has developed into a fine attacking full-back, and will also help stretch the play with energetic forward runs.
It was the threat of Baines that Rafa Benitez was particularly concerned about last season, and the Spaniard switched - after an unusual, messy experimentation with a 4-3-3 - Ramires to the right flank to counter the left-back's attacking threat. Mourinho has used Ramires on the flank in pre-season, and the positional change can't be ruled out - but with the Brazilian starting all four fixtures to date in the centre of midfield, it feels more likely that Andre Schurrle will start on the right. The German's work ethic and willingness to track back has been a highlight of the season to date, and he'd be ideal for helping protect Branislav Ivanovic from overloads, before springing forward on the break.
Indeed, it feels like Chelsea's counter-attacking will be the predominant feature of this clash, considering Everton's possession statistics to date and Mourinho's love of rapid, organised transitions. With Everton likely to push their full-backs high up the pitch, the likes of Eden Hazard and Willian will thrive on the space vacated in wide areas - and with Fernando Torres's against Bayern Munich capping off a wonderful counter-attacking move, you get the feeling like Chelsea's ability to transition rapidly into attack is improving.