Mourinho said United, who are four points ahead of third-placed Liverpool who have played one more game, have to be cautious of their opponents who are desperate to secure points in a bid to ensure top-flight survival.
'I was not going to celebrate like insane, for me we should play with great focus and intensity and try and kill the top four situation and be more stable in second.
"The first thing is stability at training level, stability during the working week".
The Portuguese gaffer revealed what he told Pogba after the derby win: "I told Paul after the City game I don't expect him to be man of the match every week".
"Congratulations to Manchester City on their Premier League title win", read the message on United's Twitter account.
'Paul had a yellow card and before that he had a situation not for a second yellow but you never know in football, so I reacted to that.
"I think he has to try to keep that level of stability and from that stability will appear the special match with the special performance, like happened against City", said Mourinho.
"I have won titles, I would not be happy if someone said I won title because someone lost a match", he added.
Certainly, in a more advanced role, Pogba was devastating against City and Mourinho clearly believes his £89 million ($126 million) star is capable of repeating that form in the future. "We are not going to do anything insane", said Mourinho.
"I enjoy coming each day to the changing room, going out to train, seeing stadiums full of people and having a photograph taken with fans that wait for us at Carrington".
"They won the title because they were the best team".
'The commitment, the desire, and I asked if Pogba can do that all the time, the way he played against City.
"I think he finished sixth last season and now they're second in the league, so I think it's been a big improvement".