Chelsea have sacked manager Roberto Di Matteo after eight months in charge at Stamford Bridge.
The Italian guided the club to a Champions League and FA Cup double last season after taking over as interim manager from Andre Villas-Boas in March, and was rewarded with a permanent two-year contract in the summer.
But after a 3-0 defeat to Juventus in the Champions League on Tuesday, which put the holders on the brink of elimination, and four games without a win in the Premier League, The Blues have parted company with the 42-year-old.
"Chelsea Football Club has parted company this morning with manager Roberto Di Matteo," a club statement read.
"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.
"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."
Di Matteo, who made 175 appearances in six years as a player in west London, was the club's eighth coach during Roman Abramovich's 10 seasons as owner.
Former Liverpool manager Rafa Benitez and ex-Chelsea boss Avram Grant has been heavily linked with taking over on an interim basis until the end of the season, as Chelsea seek to put their domestic and European campaign back on track.
The assistant to Villas-Boas last season, Di Matteo replaced the Portuguese boss in March and claimed the first European Cup in the club's history, knocking out reigning champions Barcelona on the way to the final, before a penalty shoot-out win over Bayern Munich.
The departure of Didier Drogba in the summer signalled a new era at Stamford Bridge, with substantial money spent on the likes of Eden Hazard and Brazilian international Oscar.
Di Matteo took Chelsea to the top of the Premier League in mid-October as the club produced the free-flowing football Abramovich has craved during his nine-year tenure as owner, while they also reached the last eight in the Capital One Cup.
But defeats in the Champions League to Shakhtar Donetsk, and in the league to Manchester United, sparked a run of two wins in eight games, culminating in an emphatic defeat to Serie A champions Juventus which puts the club on the brink of becoming the first defending champions to be eliminated at the group stage in the competition's history.
In 42 games as Chelsea manager, Di Matteo claimed 24 wins, nine draws and nine defeats and leaves the side third in the Premier League table ahead of the visit of league champions Manchester City on Sunday.