Mourinho, who guided the Blues to two Premier League titles during his spell at Stamford Bridge between 2004 and 2007, has been heavily linked with a move back to his former club, with Rafael Benítez set to depart in the summer.
But although Blues playmaker Mata admits that Mourinho’s credentials are second-to-none, the Spaniard insists Chelsea must remain focused on the run-in under interim boss Benítez.
“They [Chelsea] keep fond memories of Mourinho,” Mata told Movistar. “They did very well, won titles and the fans will keep a great memory.
“But today Mourinho is the coach of Real Madrid and Benítez of Chelsea. We have to be focused on that.”
Mourinho, who led Inter Milan to an historic treble before taking the reins at Real Madrid, hinted that he may return to one of his former employers when he leaves Spain.
“Everyone knows I have an adventurous spirit,” Mourinho is quoted as saying by the Sun. “It’s not easy for my family.
“We’ll see what happens. After England, Portugal, Italy and Spain, it’s not easy to find a new destination.
“It could be a destination where I have coached before. There are things that may be about to happen no one could imagine.”
Mourinho has also been linked with a move to cash-rich Ligue 1 side Paris Saint-Germain.