Liverpool will welcome Chelsea to Anfield on Thursday for the biggest midweek fixture in the 2020-21 Premier League.The hosts have been in free fall since the turn of the year in what has turned out to be inarguably one the worst title defences in English football history. In stark contrast, Chelsea have rediscovered their best form since the appointment of Thomas Tuchel.So, one of several sub-plots in the game is about whether the Blues will become the latest club to take down Liverpool on their own patch.Anfield was once the most feared ground in all of Europe, with Jurgen Klopp's men going almost four years without suffering a defeat at home. However, since Burnley did what 68 others before them could not do, Liverpool have lost three consecutive league games at home; Brighton, Manchester City and Everton have all taken three points away from their league visits to Anfield.A much-needed victory against Sheffield United on Sunday ended Liverpool's four-game skid as Chelsea played out a dour goalless draw with Manchester United.In many ways, this is a straight knockout in the race for the top four, as just one point separates both sides in the league table.With several world-beaters available for selection by both managers, let's take be a look at a hypothetical combined XI of Liverpool and Chelsea. A 4-3-3 formation has been considered.Goalkeeper: Alisson Becker (Liverpool)Alisson has been below par in recent weeks.Alisson has been one of the worst culprits in Liverpool's recent skid. The formerly impenetrable goalkeeper has suddenly become shaky in recent weeks, making several mind-boggling errors in succession.Alisson is the first Liverpool player to make 2+ errors leading to a goal in a Champions League or Premier League game since Loris Karius in the UCL final against Real Madrid. 😳 pic.twitter.com/2Xa28QwOGw— Squawka Football (@Squawka) February 7, 2021Edouard Mendy has impressed since signing for Chelsea and has helped bring stability to what was previously a problem area. The Senegal international is, however, not without a blemish. His struggles while playing out from the back serves as a potential Achilles heel for opponents to explore.So, considering his superior experience in the competition, Alisson gets the nod.Left-Back: Andrew Robertson (Liverpool)Andrew Robertson is the best left-back in the Premier League at the moment.Andrew Robertson has raised the bar for left-backs over the last few years. He has played a key role in the success enjoyed by Liverpool since his arrival from Hull City.This season, however, has seen a drop off in performance from the Scotland captain, which has in turn has affected Liverpool's fortunes.Nevertheless, he still edges out the Chelsea left-backs, chiefly because Tuchel's appointment has seen Ben Chilwell getting replaced by Marcos Alonso, who hasn't impressed enough.Centre-backs: Thiago Silva and Kurt Zouma (both Chelsea)Chelsea vs Wolverhampton Wanderers - Premier LeagueKurt Zouma has been one of the casualties since Tuchel's appointment, with his place taken by the rejuvenated Antonio Rudiger.However, the fact that Liverpool have been decimated by injuries, particularly in the centre of defence, automatically rules out all their central defenders. Jurgen Klopp has used no fewer than 17 different centre-back combinations this season, with midfielders forced to play at the heart of defence.Only one Liverpool center-back has played 10 league games this season, which is less than an adequate number to properly judge them.By contrast, Thiago Silva has been impressive at the heart of defence for Chelsea; he has adapted to his new role as an on-field leader effortlessly. Injury has robbed him of the chance to impress under Thomas Tuchel, but their history together suggests he could play a key role when he returns to full fitness.36 - Thiago Silva is the sixth oldest player to score for Chelsea in the Premier League (36y 46d), while only Glenn Hoddle (36y 150d) scored his first goal for the Blues at an older age than the Brazilian. Vintage. pic.twitter.com/lNgm6ZxdyM— OptaJoe (@OptaJoe) November 7, 2020Kurt Zouma was also a mainstay under Frank Lampard, starting 15 of the club's first 17 Premier League matches. He also proved to be a considerable goal threat, with his four goals at one point making him Chelsea's second-highest goal-scorer.Right-back: Trent Alexander-Arnold (Liverpool)Liverpool vs Manchester City - Premier LeagueLike Robertson on the opposite flank, Trent Alexander-Arnold is a crucial piece of Jurgen Klopp's attacking arsenal.However, this season has seen the England international perform below expectations. He has not looked as assured going forward, and his previously pristine crosses have become wildly inconsistent, while he has also frequently lost possession.Nevertheless, Chelsea's right-back Reece James, who although is on the right trajectory, has not done enough this season to dislodge the Liverpool number 66 from this hypothetical XI.Reece James has also not been a mainstay under Tuchel, with Callum Hudson-Odoi preferred in the wing-back role instead.