Chelsea are facing yet another crisis following Sunday's 6-0 defeat away to Manchester City.Losing by a six-goal margin meant the Blues lost ground in the race for the top four and dropped below Manchester United and Arsenal into sixth.Maurizio Sarri's role as manager is now under threat, too, and a lot of the players have been accused of not being good enough.Individual mistakes plagued Chelsea's display at the Etihad Stadium as Marcos Alonso, Ross Barkley, Kepa Arrizabalaga and Cesar Azpilicueta all made errors leading to goals.Alonso failed to track Bernardo Silva for City's opener, Barkley headed the ball straight to Sergio Aguero for his second of the game and Kepa should have gone better for Ilkay Gundogan's strike.As for Azpilicueta, who is usually so reliable at the back for Chelsea, the Spaniard gave away a penalty for an ill-judged sliding tackle on Raheem Sterling in the box.There was nothing that could be done about City's other two goals, though.Big changes are needed at Chelsea if they're going to keep fighting for a place in the Champions League and one position that needs immediate attention is left-back.Alonso has been a weak link for Chelsea all season and against City he was absolutely dreadful, both defensively and with his decision making going forward.There was one moment at 4-0 down that summed up Alonso's performance when he had the chance to put Eden Hazard through down the left but crossed for N'Golo Kante instead.Bear in mind that Kante is only 5' 6" tall, yet Alonso opted for the Frenchman in the box over Chelsea's best player, who had acres of space.

So poor. Chelsea fans have been saying for a long time that Alonso isn't good enough and they might just be right based on this evidence.

That being said, Emerson wasn't much better during the recent 4-0 defeat away to Bournemouth, so perhaps it's a case of bringing in a brand new left-back this summer.