Mikel Obi told BBC World Service’s Sportsworld that Mourinho killed him because he got sent off on his first game for the Blues.
The Middlesbrough midfielder said he was quite slow to the pace expected of him by Mourinho in his early days at Stamford Bridge.
The 31-year-old midfielder spent 11 years at Chelsea, winning the Champions League, two Premier League titles and three FA Cups before joining Chinese side, Tianjin Teda, in 2017.
“Got sent off on my first game. Mourinho killed me. The speed of the game took me a while to understand it,” Mikel said.
“I was a very naughty boy. I’ll get up to speed but I was late to training many times. I was wearing the wrong dress codes.
“Mourinho was very firm with me because he wanted me to learn and learn very fast because he brought me in.
“With Mourinho, there are no excuses. I was put in a very naughty corner a few times. It took me a while to understand where I am and I had to learn very fast.”