Chelsea have put Avram Grant in charge of their first team following the shock departure of Jose Mourinho, the club announced on Thursday.
Grant, previously the director of football at Stamford Bridge, will take charge along with Mourinho's former assistant Steve Clarke.
It was not clear if Grant, a close friend of Chelsea's Russian owner Roman Abramovich, will be given the manager's job on a long-term basis.
But the Israeli will be in charge when Chelsea face champions Manchester United at Old Trafford on Sunday.
The 51-year-old's promotion came hours after Mourinho's trophy-laden three-year reign at Stamford Bridge ended with the announcement that he was leaving the club "by mutual consent".
The self-described "special one" paid a brief visit to the club's state-of-the-art training complex to the west of London on Thursday morning to say his goodbyes to the players he guided to five trophies in three seasons, before driving away for the last time.
Mourinho's time in charge ended in the early hours of Thursday morning, his fractious relationship with Abramovich having finally reached breaking point over the manager's failure to deliver the kind of flamboyant football craved by the Russian billionaire.
Manchester United's stylish reclamation of the Premier League title last season increased Abramovich's disillusionment with Mourinho's pragmatic approach and Tuesday's disappointing 1-1 UEFA Champions League draw with Norwegian side Rosenberg, watched by fewer than 25,000 fans, proved to be the final straw.
With hindsight, Mourinho's pre-match comments about the need to buy the best eggs to make the best omelette, a clear dig at Abramovich's transfer policy, were a clear signal that simmering tensions behind the scenes were about to boil over.
Mourinho came close to being ousted last season when Abramovich failed in an attempt to persuade former Germany coach Jurgen Klinsmann to succeed the Portuguese.
Although Grant has been put in the hot-seat now, a fresh move to lure Klinsmann, who is based in California, back to Europe cannot be ruled out.
Russia manager Guus Hiddink, who knows Abramovich well, and the former Monaco and Juventus boss Didier Deschamps, who briefly played for Chelsea towards the end of his illustrious career, have also been touted as possible long-term successors to Mourinho.
Grant's introduction to the backroom staff, initially resisted by Mourinho, had apparently been accepted by the Portuguese as part of a summer truce between him and the club owner.
But it now appears that tensions over Abramovich's desire to interfere in team affairs had continued to fester, culminating in a terse statement posted on the club's website.
It read: "Chelsea Football Club and Jose Mourinho have agreed to part company today (Thursday) by mutual consent."
With both sides keeping quiet on the precise nature of the dispute that triggered the final meltdown in relations, negotiations over compensation for the remaining three years on Mourinho's £5m-a-year contract were continuing.
Grant was recruited from Portsmouth partly with the aim of improving the performances of Andriy Shevchenko, whose presence in the Chelsea squad was a running sore in the the relationship between Abramovich and Mourinho.
The manager had never made any secret at his frustration with the Ukrainian striker's failure to make an impact in the English game following his £30m move from AC Milan at the start of last season.
Shevchenko, once regarded as the deadliest finisher in European football, was widely seen as Abramovich's signing and the Russian reportedly holds Mourinho responsible for his failure to get the best out of him.
Mourinho made his reputation by guiding FC Porto to Champions League glory in 2004 and then transformed the English football landscape after taking over at Stamford Bridge in June 2004.
In his first season in charge he ended the club's 50-year wait for an English title, a feat he repeated the following season as well as delivering the FA Cup last season and the League Cup in 2005 and 2007.
Although he has been generously bankrolled by Abramovich, Mourinho's record backs up the "special one" claim he made at his first press conference in England.
In his 185 games in charge, Chelsea won 124, drew 40 and lost 21, a record that includes a 60-match unbeaten run in Premier League matches at Stamford Bridge.