Chelsea have made a good start to the season, but have lost their last two games across competitions. The Blues lost to Manchester City last weekend in the Premier League before losing to Juventus in the Champions League on Wednesday. That has sent Thomas Tuchel back to the drawing board.The Champions League holders have a lot at stake season, so they need to improve their performances quickly. They have been nowhere near their best in September and have shown signs of exhaustion. Chelsea might have to spend big in January if they want to retain the Champions League or win the Premier League title this season.On that note, here are five players Chelsea should target in the January transfer window:#5 Niklas SuleFC Bayern München vs Dinamo Kiev: Group E - UEFA Champions LeagueNiklas Sule is out of contract at the end of the season, and might be available for a cut-price. Bayern Munich do not let most of their players walk away for free, and will be looking to cash in if they have the chance to so.Chelsea have been linked with Niklas Sule in the past, so they might want that to count in January. Thomas Tuchel is reportedly said to be a big fan of the German., With Sule likely to be available for cheap, the Blues should look to snap him up.Goal@goalChelsea are stepping up their interest in Bayern Munich defender Niklas Sule, according to The Athletic 🇩🇪2:33 AM · Apr 19, 20213016178Chelsea are stepping up their interest in Bayern Munich defender Niklas Sule, according to The Athletic 🇩🇪 https://t.co/s1lKiizk01The main reason Chelsea need a centre-back is because of Antonio Rudiger's contract situation. The German is yet to pen a new deal, and Thiago Silva is also at the end of his career.Chelsea need a centre-back urgently, and Niklas Sule might be the ideal solution for now.#4 Franck KessieFranck Kessie could be an option for Chelsea.Franck Kessie is heading towards the end of his contract at AC Milan, and will be available for a cut-price. He could be headed to Chelsea, as he would offer experience and fit well in Thomas Tuchel's system.Saul Niguez was signed by Chelsea on loan from Atletico Madrid this summer. The Spaniard has not made a good impression so far, and the loan is highly unlikely to turn into a permanent move.Bolarinwa Olajide@iambolarFranck Kessie in 2017: "I like the Premier League and in particular Manchester United - the club I dream of playing for. Chelsea? That is also a big club, nobody would turn them down, but I dream of United."04:26 AM · Mar 13, 2021718Franck Kessie in 2017: "I like the Premier League and in particular Manchester United - the club I dream of playing for. Chelsea? That is also a big club, nobody would turn them down, but I dream of United."Chelsea need a midfielder, as they cannot rely on Jorginho to play as a no.6 in every game. Ruben Loftus-Cheek has shown his ability to play there. But given that he is just getting into form and considering N'Golo Kante's recent injury history, Chelsea could be well served by signing Kessie.