Alexis Sanchez: Chilean can make City invincible but who should Arsenal sign to replace him?

With Alexis Sanchez seemingly likely to move to Manchester City in January, Alex Keble assesses how he would fit in at the Etihad and how Arsenal can replace him...

As the newspaper reports stack up it is becoming increasingly clear that Alexis Sanchezwill get his wish this month and join Manchester City for a fee of around £35 million.

The transfer would beg many questions: why did Arsenal refuse to sell in August if they are willing to let the Chilean leave now? And why does Pep Guardiola feel the need to add yet more firepower to a team already 15 points clear at the top of the Premier League table?

The former is a question only Arsene Wenger knows the answer to, but the latter is easier to comprehend. Guardiola has shown an unexpected thirst for breaking records this season, not content with leading the hunt for trophies but keen to make this a legendary season for Manchester City. He wants the Champions League, of course, but he is also desperate to go the entire league season unbeaten. Sanchez helps the cause on both counts.

What Sanchez will bring to City

Many fans and pundits are unsure how Sanchez will fit in at City given their strength in attack this season, and the addition of a 29-year-old looks slightly incongruous - worrying, even - given his arrival could scupper the development of Leroy Sane and Raheem Sterling. However, it is far more likely that Sanchez will be deployed as a false-nine rather than a winger under Guardiola, playing in a role he briefly enjoyed under the Catalan at Barcelona and in which he excelled last season for Arsenal.

Sergio Aguero continues to disappoint Guardiola despite his excellent goalscoring return, and if you look beyond the numbers it is easy to see why. Tactical fluidity and overloading central attacking midfield with bodies is a vital aspect of Guardiola's aesthetic, but Aguero has consistently shown he is incapable of adapting to become a deeper forward. Instead, the Argentine rarely contributes outside the penalty area or drops short to bring others into play. Consequently City become slightly more direct with Aguero in the side, relying increasingly on David Silva and Kevin de Bruyne.

Gabriel Jesus's two-month injury layoff means Aguero will be alone up front for the foreseeable future without reinforcements, explaining Sanchez's imminent arrival. The Chilean was inspirational in 2016/17 when playing up-front; his tireless energy and constant movement meant he could simultaneously play as a traditional forward - making runs on the shoulder, like Aguero - and as a false-nine, dropping off to bring his teammates into the game.

With such a potent weapon up-front, particularly one capable of conjuring goals out of thin air, it is now increasingly likely City will go the entire season undefeated. It was already difficult to see how anyone could outscore this team (Crystal Palace came close, but City were half-filled with reserves that day), but with Sanchez flitting across the front three it looks impossible. Sit deep and City will grind you down; be bold and Sanchez, magical when given space to break into, will cut you to pieces.

You can see why the Sportsbook are pricing them at 16/5 to go the entire season unbeaten.

Mahrez is a rare talent and can fill Sanchez's shoes

Such inventive attackers are difficult to find, but there are three main options for Arsenal who could potentially perform a similar job as Sanchez. His role at Arsenal is very different to the one he will undertake at City; the Gunners are looking for an inside forward with piercing directness to compliment the delicacy of Mesut Ozil.

Riyad Mahrez is the most obvious like-for-like. The Algerian should be available for around £60 million this window, and given his recent form it is the perfect time to sign Leicester City's chief creator. Mahrez's renewed energy is a reminder of his rare talent of weaving through tight spaces and scoring key goals - things Ozil cannot do and Arsenal desperately need to replace. Mahrez to join Arsenal this month is currently priced at 7/1.

Thomas Lemar, at around £90 million, is perhaps overpriced in the current market but is relatively similar to Mahrez - albeit less experienced and less obviously suited to Premier League football. The AS Monaco youngster is a bigger gamble for Arsene Wenger, but if Arsenal are keen on signing Lemar they should act now. Not only will interest intensify in the summer, but Lemar could do with six months to adapt to life in England before Ozil leaves and the pressure upon his shoulders increases dramatically. However, a move doesn't seem likely according to the betting markets; Lemar to join Arsenal is currently 12/1.

Nabil Fekir is the final option for Arsenal. Linking up with his former Lyon team-mate Lacazette, there is no reason why Fekir cannot be a success at the Emirates. He does not possess the same technical subtlety as Sanchez but is tall and powerful, meaning he could potentially work well alongside Ozil. Fekir has scored 13 goals and bagged four assists in Ligue 1 this season, making him decent value at £60 million.

Unlike Liverpool - who are reportedly interested in all three of these playmakers - Arsenal will need to act now should Sanchez join City; the Chilean's departure wouldn't just turn Guardiola's side into potential Invincibles, it would also weaken Arsenal to the extent that Champions League qualification - already unlikely at 3.90 - becomes virtually unthinkable. That's why, despite some bemusement surrounding its necessity this month, Sanchez's move to Manchester City could be a season-defining moment for two of England's biggest clubs.