Roman Abramovich's nine-month itch
Of the six managers (not including Ray Wilkins) that Chelsea owner Roman Abramovich has appointed since the sacking of Jose Mourinho in 2007, four of them have been sacked part way through their ninth month in charge.
The only boss to survive his ninth month since Mourinho is Carlo Ancelotti, who was sacked in 2011 with a League and Cup double under his belt.
Here's how long they (haven't) lasted:
Roberto Di Matteo: 262 days (8.7 months)
Andre Villas Boas: 257 days (8.6 months)
Carlo Ancelotti: 721 days (24 months)
Guus Hiddink (caretaker manager): 109 days (3.6 months)
Luiz Felipe Scolari: 244 days (8.1 months)
Avram Grant: 248 days (8.3 months)
Jose Mourinho: 1206 days (40.2 months)