Since the ex-FC Porto manager left Stamford Bridge, the Blues have won just one FA Cup under the stewardship of Avram Grant, Luiz Felipe Scolari, Guus Hiddink and now Carlo Ancelotti.
The latter looks set to end the club's trophy drought this term although Chelsea face Mourinho's Inter side in the last 16 of the Champions League.
Mourinho claimed in Nuts: "Chelsea have suffered in the last two years and it's no coincidence that their decline happened after I left. We had a unique relationship as a manager, players and fans and, when you break that, it's not easy to fix.
"They've had a lot of coaches since and maybe some didn't have the mentality for the club. Maybe they tried to change too much of what we put in place.
"I knew there was no time for a long-term plan with the owner they have at Stamford Bridge. You must win the title in your first season or say bye-bye. I gave them what they needed but I always knew it wasn't a job that would last forever.
"Maybe they would have been better off sticking with me than changing manager when they did."