José Mourinho has admitted he has never been close to Roman Abramovich despite Chelsea’s owner twice appointing him and the Portuguese being the most successful manager in the club’s history.

Mourinho takes Manchester United to Stamford Bridge on Sunday to face Chelsea for the first time in a domestic game. He was in charge from 2004-07 and 2013-15, winning three Premier League titles, one FA Cup and three League Cups.

Yet he is clear Abramovich and he shared only a business relationship. Mourinho also accepts there may be a hostile reception from fans but says he will not celebrate “like a kid” if United score.

“He was never my friend,” Mourinho said of Abramovich. “We always had the relationship of owner-manager; a very respectful relationship. We were never friends. We were never close to each other. So, no, he is just a person that I keep very respected. “If you ask me: ‘If my team scores a goal am I going to celebrate like a crazy kid?’ No. I think I can control the emotion of that situation. Am I going to have a negative reaction if the crowd has something negative with me? No. I think, again, I have the maturity enough to control the emotion. I have lots of respect.”

Mourinho was sacked by Chelsea last December after a series of negative results. He denied the experience had improved him.

“That period came in a part of my career when I was already a grown man,” he said. “I was already a stable manager, emotionally strong. I was not a kid. It didn’t happen in the first years of my career. It happened when I had already so many years. I think I got it in a positive way. I was lucky to have a big club like Man United who focused on my career and not in my last three months.

“I was lucky enough to have the chance to stay in the competition I most love and to stay in a big club like Man United, with a big project, with a big challenge like I have in my hands.”

United are in seventh, two points and two positions behind Chelsea, after eight matches. Despite what promises to be a febrile atmosphere, Mourinho insists his prime concern is the game.

“To say I care is not true,” he said of the Chelsea supporters’ welcome for him. “To be honest, when I go to a football match I am not focused on that. I am more focused on the game. I try to prepare myself for the match, so I cannot say I care. What can I expect? I don’t know. They can think about me and remember our great relation and have a good reaction. They can look at me and say: ‘For 90 minutes he is Man United manager and he is playing against us, so he is not someone we like at this moment.’”

When it was put to Mourinho that the fans retain a fondness for him because of his achievements at the club, he said: “I know but I did my job. They gave me their love and they gave me their support. That is the most important thing. If now I go there … and they decide to have a different approach I will always respect them. But from me, you are not going to have, ever, a bad word about any one of my previous clubs. I keep always a very good feeling. It doesn’t matter what is going to happen. But, it is my nature. It is my job. It is my new club. On Sunday I will go there to try and do my job.”

Despite his history with Chelsea, Mourinho will urge his side to concentrate solely on the contest. “We have to try to forget it,” he said. “We have to try to do the job. I played there with Inter. I tried to do my job.

“What Man United fans can expect from me is more important. What Man United fans can expect from me is to play against Chelsea the same way I play against Fenerbahce, Liverpool, anyone – because that is my job.”