Chelsea manager Roberto Di Matteo has been sacked following a run of poor form.
The Italian won 24 of his 42 games in charge of the club but, after their 3-0 defeat to Juventus left them in danger of missing out on the knockout stages of the Champions League, Chelsea have decided to end his tenure.
Former Barcelona coach Pep Guardiola and ex-Liverpool manager Rafa Benitez have emerged as the early favourites to replace Di Matteo.
However, Harry Redknapp and former Stamford Bridge boss Jose Mourinho have also been mentioned as contenders for the position.
"The team's recent performances and results have not been good enough and the owner and the Board felt that a change was necessary now to keep the club moving in the right direction as we head into a vitally important part of the season," read a statement on the club website.
"The club faces a difficult task ahead in qualifying for the knockout stages of the UEFA Champions League as well as maintaining a strong challenge for the top of the Premier League while competing in three other cup competitions.
"Our aim is to remain as competitive as possible and challenge strongly on all fronts.
"The owner and the Board would like to thank Roberto for all he has done for the club since taking over in March.
"Roberto helped guide us to an historic Champions League victory and a seventh FA Cup. We will never forget the huge contribution he has made to this club's history and he will always be welcome at Stamford Bridge.
"The club will be making an announcement shortly regarding a new first team manager."
Chelsea's defeat in Turin means they must beat Nordsjaelland in their final group game in a fortnight's time and hope Juventus lose to the already-qualified Shakhtar Donetsk in order to reach the last 16.
Allied to a run of four Premier League games without a win, Di Matteo's position as manager at Stamford Bridge had come under increasing scrutiny just months after signing a two-year contract.
Di Matteo was handed a permanent deal after leading the Blues to Champions League and FA Cup success having replaced previous boss Andre Villas-Boas in March.
However, he has become the latest manager to fall victim to Roman Abramovich's axe after risking the owner's wrath by dropping record signing Fernando Torres for the Juventus game and radically overhauling his tactics.
Di Matteo had taken more than an hour to emerge for his post-match press conference before taking full responsibility for the result.
He said: "I'm responsible for the result. I'm responsible for the performance. It's a negative evening for us.
"If anyone has to take the blame, it's me. I selected a team I was convinced was the right team to win against Juventus, or get at least a draw, so the blame belongs to me."
He added: "I'm responsible for positive and negative results. This is what I do."
Are Chelsea right to sack Roberto di Matteo?