Chelsea finished eight points clear last season and won the League Cup, but have lost nine of their 16 league games so far and are 16th in the table, one point above the relegation places.
Mourinho`s final match was Monday`s 2-1 defeat at leaders Leicester City.
Pep Guardiola, Guus Hiddink, Juande Ramos and Brendan Rodgers have all been touted as possible successors as Blues owner Roman Abramovich begins another managerial search.
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