Mata should line up against Chelsea for the first time since leaving them to join Man United in January 2014.
The Spaniard will be looking to get one over Mourinho as he reportedly preferred Oscar due to his superior defensive contribution.
Mourinho insisted he has been pleased to see Mata do well at United but that he is not particularly concerned by his return to London.
When asked about Mata, Mourinho said: ”I have no thoughts. He is a player with a history in this club, everyone has respect for him as a player. If things are going well, everyone is happy for him. He is a very correct boy and a great professional.”
Mata is currently in the form of his life at United and Chelsea would be unwise not to have made special plans for him.
Cesar Azpilicueta will be confident of keeping tabs on the 26-year-old but Manchester City’s Gael Clichy would have said the same prior to their clash with United last weekend. As it turned out, Mata regularly turned him inside-out on the way to a 4-2 victory.