After a fruitful period of experimentation, Arsenal manager Arsene Wenger reverted to type against Newcastle United on Saturday (16 December), plumping for a flat back four after setting his side out in a 3-4-3 formation for the majority of 2017. The decision was partly forced upon Wenger due to the unavailability of some key defensive figures, but the Frenchman may see fit to utilise the same defensive system against Liverpool, who no doubt have fond memories of the previous meeting between the two sides.
Jurgen Klopp's side exploited every aspect of the Gunners that they could have possibly exploited back in August, running out rampant 4-0 winners over Wenger's side thanks to goals from Roberto Firmino, Sadio Mane, Mohamed Salah and Daniel Sturridge.
Wenger's team selection on that fateful day was questioned no end: Why did Alex Oxlade-Chamberlain start? Why didn't Alexandre Lacazette? Why was Hector Bellerin deployed out of position on the left when Sead Kolasinac was fit and available? Why was nothing done to try and counter Liverpool's rampant central midfield, which was allowed to run riot?
Lessons would have no doubt been learnt by Arsenal, who could take Liverpool's spot in the Champions League position with a win on Friday. Klopp will presumably unleash the 'Fab Four' as he strives for a similar result to the one garnered in August, but Wenger has his own attacking triumvirate that could wreak havoc against the Merseysiders.
Alexis Sanchez, Alexandre Lacazette and Mesut Ozil were unsurprisingly rested for Arsenal's 1-0 victory against West Ham United in the Carabao Cup on Wednesday, and the esteemed trio should be afforded starts against Liverpool. Ozil's wondrous volley helped the Gunners claim all three points against a perhaps unfortunate Newcastle and the Germany international has shown his effectiveness in recent matches against tough opposition, with strong performances in the defeat by Manchester United and win over Tottenham Hotspur.
With Olivier Giroud suffering a hamstring problem against West Ham, Wenger must choose between Lacazette and Danny Welbeck to spearhead his attack. Taking into account Lacazette's pedigree and decent goalscoring return this season, along with Welbeck's struggle with a recent groin problem, the Frenchman seems like an obvious for his compatriot Wenger, while Sanchez, whose commitment and application has been criticised in recent weeks, cannot be left out of a game of such magnitude.
In the midfield, Wenger has little wriggle room. Granit Xhaka and Jack Wilshere started against Newcastle with Aaron Ramsey out injured until the new year, and the pair will almost certainly maintain their respective places in Arsenal's starting line-up given the dearth of adequate replacements available to Wenger.
Frances Coquelin and Mohamed Elneny started in the win over West Ham on Tuesday but neither have shown that they are truly fit for purpose in big matches, which leaves an opportunity for Alex Iwobi to display his mettle against Liverpool.
Wenger has shown faith in the Nigeria international and afforded him starts against Chelsea and Manchester City earlier in the season, and the lack of quality central midfield players at The Emirates Stadium will likely see the Frenchman deploy Iwobi in a 4-2-3-1 system, with the defence boosted by the return of Kolasinac.
The Bosnian was inexplicably dropped by Wenger for the reverse fixture with the Reds in August but will presumably re-assume his place at left-back having proved his fitness against the Hammers. Kolasinac will operate next to Nacho Monreal, whose experience as a centre-half outside of a back three is limited, but the Spaniard will be partnered with the reliable Laurent Koscielny. Hector Bellerin and Petr Cech are both shoo-ins to start against Liverpool, with no real competitor for their position.