Mourinho's league leaders face Arsene Wenger's men at Stamford Bridge on Sunday, with Fabregas facing his former club for the first time since leaving in August 2011.
Fabregas has made a bright start to life at Chelsea, helping them to five wins in six Premier League matches and a three-point lead at the top of the table.
Mourinho said the Spain international would always respect Arsenal, but believes Fabregas already loves rivals Chelsea.
"Fabregas will never lose his respect and connection with a club where he arrived as a kid and left as a top player," the Portuguese tactician said.
"Arsenal made him. I wouldn't be happy if he came here saying he didn't care about Arsenal and that he forgot all that and now it's just about Chelsea.
"But I think he loves Chelsea already. He's so happy: the way he plays, the way he's a member of the squad, the way he lives in this little blue village.
"It is like he's been here for a long time. If you ask him now if he regrets the move, I'm sure he'd say no.
"If you ask him if he'd choose a different option, he'd say no. And if you ask him where he thinks he'll be in five years' time, he'd say he sees himself here in five years' time. He is Chelsea."
In the only game in which Chelsea have dropped points in the league so far this season, the club's former midfielder Frank Lampard scored a late equaliser for Manchester City to secure a 1-1 draw.
Mourinho urged Fabregas to keep his emotions in check – like Lampard – if he gets on the scoresheet against Arsenal.
"In this game, if he should score then I don't care whether he celebrates or not," said Mourinho.
"When my Inter scored three times against Chelsea I didn't celebrate. But you can't imagine how happy I was.
"The point is not whether you celebrate or not, but control your emotion and not celebrating is nice. Show some respect. But if you can't control your emotion, you can't. It's all right."
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