With the Blues boss under pressure, Pep Guardiola has emerged as the front-runner to replace the Special One, according to the latest bookmaker odds.
As the managers of Real Madrid and Barcelona respectively, Jose Mourinho and Pep Guardiola were rarely the best of friends.
So the news that the Special One's Catalan rival has emerged as the bookmakers' favourite to become the next permanent manager of Chelsea will be all the more galling to the Portuguese coach.
Mourinho is under increasing pressure at Stamford Bridge, after a 3-1 defeat to Everton left the Pensioners 11 points off Premier League leaders Manchester City.
Chelsea have accumulated just four points from the first five top-flight games this term, in the club's worst start to a league season in 29 years.
That run of results has increased the pressure on Mourinho, with bookmakers already slashing the odds on the Portuguese manager leaving his post.
According to Oddschecker, Guardiola is the favourite to be named the next permanent Chelsea manager, with the Bayern Munich coach on at 4/1.
Diego Simeone and Carlo Ancelotti are next in the betting, with the pair both offered at around the 12/1 mark.
Bizarrely, City boss Manuel Pellegrini is next in the betting at around 14/1 with Italy national team coach Antonio Conte also among the early front-runners at 16/1.
Though not always the most accurate indicator, the prices nevertheless make for interesting reading and not simply to Chelsea fans.
Manchester City have long been linked with a move for Guardiola but the latest prices suggest they could be beaten to the punch by their Premier League rivals.
Whether that proves to be the case, is another matter.